Major hierarchy reorganization; see README.

copy-to-ide and Makefile updated to conform; .gitignore added;
LICENSE added

25 files changed, 3271 insertions, 0 deletions

diff --git a/libmaple/adc.c b/libmaple/adc.c
new file mode 100644
index 0000000..7169824
--- /dev/null
+++ b/libmaple/adc.c
@@ -0,0 +1,97 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/18/09 02:34:47
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file adc.c
+ *
+ *  @brief Analog to digital converter routines
+ */
+
+#include "stm32f10x_rcc.h"
+#include "adc.h"
+#include <stdio.h>
+#include <inttypes.h>
+
+/* The ADC input clock is generated from PCLK2/APB2 divided by a prescaler
+ * and it must not exceed 14MHz.
+ *
+ * ADC1 and ADC2 are clocked by APB2
+ *
+ * 1) Power on by setting ADON in ADC_CR2
+ * Conversion starts when ADON is set for a second time after some
+ * time t > t_stab.
+ *
+ * Up to 16 selected conversion must be selected in ADC_SQRx
+ *
+ * Single conversion mode:
+ * Set the ADON bit in the ADC_CR2 register
+ * Once the conversion is complete:
+ *  Converted data is stored in ADC_DR
+ *  EOC flag is set
+ *  Interrupt is generated if EOCIE is set
+ *
+ * Calibration:
+ * Calibration is started by setting the CAL bit in the ADC_CR2 register.
+ * Once calibration is over, the CAL bit is reset by hardware and normal
+ * conversion can be performed. Calibrate at power-on.
+ *
+ * ALIGN in ADC_CR2 selects the alignment of data
+ *
+ * IMPORTANT: maximum external impedance must be below 0.4kOhms for 1.5
+ * sample conversion time.
+ *
+ * At 55.5 cycles/sample, the external input impedance < 50kOhms*/
+
+void adc_init(void) {
+    /* PCLK2 is the APB2 clock */
+    RCC_ADCCLKConfig(RCC_PCLK2_Div6);
+
+    /* Enable ADC1 clock so that we can talk to it */
+    RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
+
+    /* Put everything back to power-on defaults */
+    RCC_APB2PeriphResetCmd(RCC_APB2Periph_ADC1, ENABLE);
+    RCC_APB2PeriphResetCmd(RCC_APB2Periph_ADC1, DISABLE);
+
+    ADC_CR1  = 0;
+    ADC_CR2  = CR2_EXTSEL_SWSTART | CR2_EXTTRIG;  // Software triggers conversions
+    ADC_SQR1 = 0;
+
+    /* Up the sample conversion time to 55.5 cycles/sec, see note above  */
+    /* TODO: fix magic numbers  */
+    ADC_SMPR1 = 0xB6DB6D;
+    ADC_SMPR2 = 0x2DB6DB6D;
+
+    /* Enable the ADC  */
+    CR2_ADON_BIT = 1;
+
+    /* Reset the calibration registers and then perform a reset  */
+    CR2_RSTCAL_BIT = 1;
+    while(CR2_RSTCAL_BIT)
+        ;
+
+    CR2_CAL_BIT = 1;
+    while(CR2_CAL_BIT)
+        ;
+}
+
+
+void adc_disable(void) {
+    CR2_ADON_BIT = 0;
+}
diff --git a/libmaple/adc.h b/libmaple/adc.h
new file mode 100644
index 0000000..d554b02
--- /dev/null
+++ b/libmaple/adc.h
@@ -0,0 +1,93 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/18/09 02:35:10
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file adc.h
+ *
+ *  @brief ADC prototypes and defines
+ */
+
+#ifndef _ADC_H_
+#define _ADC_H_
+#include <inttypes.h>
+#include "util.h"
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+/* Notes:
+ * The maximum input impedance on each channel MUST be below .4kohms,
+ * or face the wrath of incorrect readings...
+ * This can be changed at the expense of sample time... see datasheet
+ *
+ * Need to up the sample time if otherwise... see datasheet */
+
+/* We'll only use ADC1 for now...  */
+#define ADC_BASE                 0x40012400
+#define ADC_SR                   *(volatile uint32_t*)(ADC_BASE + 0)
+#define ADC_CR1                  *(volatile uint32_t*)(ADC_BASE + 0x4)
+#define ADC_CR2                  *(volatile uint32_t*)(ADC_BASE + 0x8)
+#define ADC_SMPR1                *(volatile uint32_t*)(ADC_BASE + 0xC)
+#define ADC_SMPR2                *(volatile uint32_t*)(ADC_BASE + 0x10)
+#define ADC_SQR1                 *(volatile uint32_t*)(ADC_BASE + 0x2C)
+#define ADC_SQR3                 *(volatile uint32_t*)(ADC_BASE + 0x34)
+#define ADC_DR                   *(volatile uint32_t*)(ADC_BASE + 0x4C)
+
+#define CR2_EXTSEL_SWSTART       (0xE << 16)
+#define CR2_RSTCAL               (BIT(3))
+#define CR2_EXTTRIG              (BIT(20))
+
+/* Bit banded bits  */
+#define CR2_ADON_BIT             *(volatile uint32_t*)(BITBAND_PERI(ADC_BASE+0x8, 0))
+#define CR2_CAL_BIT              *(volatile uint32_t*)(BITBAND_PERI(ADC_BASE+0x8, 2))
+#define CR2_RSTCAL_BIT           *(volatile uint32_t*)(BITBAND_PERI(ADC_BASE+0x8, 3))
+#define CR2_SWSTART_BIT          *(volatile uint32_t*)(BITBAND_PERI(ADC_BASE+0x8 + 2, 6))
+#define SR_EOC_BIT               *(volatile uint32_t*)(BITBAND_PERI(ADC_BASE+0, 1))
+
+#define NR_ANALOG_PINS           16
+
+/* Initialize ADC1 to do one-shot conversions  */
+void adc_init(void);
+void adc_disable(void);
+
+/* Perform a single conversion on ADC[0-16],
+ * PRECONDITIONS:
+ *   adc initialized */
+static inline int adc_read(int channel) {
+    /* Set channel  */
+    ADC_SQR3 = channel;
+
+    /* Start the conversion  */
+    CR2_SWSTART_BIT = 1;
+
+    /* Wait for it to finish  */
+    while(SR_EOC_BIT == 0)
+        ;
+
+    return ADC_DR;
+}
+
+
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+#endif
+
diff --git a/libmaple/bootVect.h b/libmaple/bootVect.h
new file mode 100644
index 0000000..5bcb42b
--- /dev/null
+++ b/libmaple/bootVect.h
@@ -0,0 +1,52 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file HardwareUsb.h
+ *
+ *  @brief Defines the maple boot vector structure
+ */
+
+#ifndef _BOOTVECT_H_
+#define _BOOTVECT_H_
+
+#define BOOTLOADER_VECT_TABLE ((uint32_t*)0x20000000)
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+typedef void (*FuncPtr)(void);
+
+typedef struct {
+  FuncPtr serial_tx_cb;
+  FuncPtr serial_rx_cb;
+  FuncPtr serial_linecoding_cb;
+  uint32_t* serial_count_in;
+  uint32_t* serial_count_out;
+  uint8_t* serial_buffer_out;
+  void* linecoding;
+  uint8_t major_rev;
+  uint8_t minor_rev;
+  void* usb_device_ptr;
+  void* usb_local_obj_ptr;
+} BootVectTable;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _BOOTVECT_H_
diff --git a/libmaple/exti.c b/libmaple/exti.c
new file mode 100644
index 0000000..bdaa204
--- /dev/null
+++ b/libmaple/exti.c
@@ -0,0 +1,279 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/18/09 02:35:22
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file exti.c
+ *
+ *  @brief External interrupt control routines
+ */
+
+#include "libmaple.h"
+#include "exti.h"
+#include "nvic.h"
+
+volatile static voidFuncPtr exti_handlers[NR_EXTI_CHANNELS];
+
+static inline void clear_pending(int bit) {
+    REG_SET(EXTI_PR, BIT(bit));
+    /* If the pending bit is cleared as the last instruction in an ISR,
+     * it won't actually be cleared in time and the ISR will fire again.
+     * Insert a 2-cycle buffer to allow it to take effect. */
+    asm volatile("nop");
+    asm volatile("nop");
+}
+
+/* For EXTI0 through EXTI4, only one handler
+ * is associated with each channel, so we
+ * don't have to keep track of which channel
+ * we came from */
+void EXTI0_IRQHandler(void) {
+    ASSERT(exti_handlers[EXTI0]);
+    if (exti_handlers[EXTI0]) {
+        exti_handlers[EXTI0]();
+    }
+
+    /* Clear pending bit*/
+    clear_pending(EXTI0);
+}
+
+void EXTI1_IRQHandler(void) {
+    ASSERT(exti_handlers[EXTI1]);
+    /* Call registered handler  */
+    if (exti_handlers[EXTI1]) {
+        exti_handlers[EXTI1]();
+    }
+
+    /* Clear pending bit*/
+    clear_pending(EXTI1);
+}
+
+void EXTI2_IRQHandler(void) {
+    ASSERT(exti_handlers[EXTI2]);
+    /* Call registered handler  */
+    if (exti_handlers[EXTI2]) {
+        exti_handlers[EXTI2]();
+    }
+
+    /* Clear pending bit*/
+    clear_pending(EXTI2);
+}
+
+void EXTI3_IRQHandler(void) {
+    ASSERT(exti_handlers[EXTI3]);
+    /* Call registered handler  */
+    if (exti_handlers[EXTI3]) {
+        exti_handlers[EXTI3]();
+    }
+
+    /* Clear pending bit*/
+    clear_pending(EXTI3);
+}
+
+void EXTI4_IRQHandler(void) {
+    ASSERT(exti_handlers[EXTI4]);
+    /* Call registered handler  */
+    if (exti_handlers[EXTI4]) {
+        exti_handlers[EXTI4]();
+    }
+
+    /* Clear pending bit*/
+    clear_pending(EXTI4);
+}
+
+void EXTI9_5_IRQHandler(void) {
+    /* Figure out which channel it came from  */
+    uint32_t pending;
+    uint32_t i;
+    pending = REG_GET(EXTI_PR);
+    pending = GET_BITS(pending, 5, 9);
+
+    /* Dispatch every handler if the pending bit is set */
+    for (i = 0; i < 5; i++) {
+        if (pending & 0x1) {
+            ASSERT(exti_handlers[EXTI5 + i]);
+            exti_handlers[EXTI5 + i]();
+            clear_pending(EXTI5 + i);
+        }
+        pending >>= 1;
+    }
+}
+
+void EXTI15_10_IRQHandler(void) {
+    /* Figure out which channel it came from  */
+    uint32_t pending;
+    uint32_t i;
+    pending = REG_GET(EXTI_PR);
+    pending = GET_BITS(pending, 10, 15);
+
+    /* Dispatch every handler if the pending bit is set */
+    for (i = 0; i < 6; i++) {
+        if (pending & 0x1) {
+            ASSERT(exti_handlers[EXTI10 + i]);
+            exti_handlers[EXTI10 + i]();
+            clear_pending(EXTI10 + i);
+        }
+        pending >>= 1;
+    }
+}
+
+
+void exti_attach_interrupt(uint8_t channel, uint8_t port, voidFuncPtr handler, uint8_t mode) {
+    ASSERT(channel < NR_EXTI_CHANNELS);
+    ASSERT(port < NR_EXTI_PORTS);
+    ASSERT(mode < NR_EXTI_MODES);
+    ASSERT(EXTI0 == 0);
+    ASSERT(handler);
+
+    /* Note: All of the following code assumes that EXTI0 = 0  */
+
+    /* Map port to the correct EXTI channel */
+    switch (channel) {
+    case EXTI0:
+    case EXTI1:
+    case EXTI2:
+    case EXTI3:
+        REG_SET_MASK(AFIO_EXTICR1, BIT_MASK_SHIFT(port, channel*4));
+        break;
+
+    case EXTI4:
+    case EXTI5:
+    case EXTI6:
+    case EXTI7:
+        REG_SET_MASK(AFIO_EXTICR2, BIT_MASK_SHIFT(port, (channel-4)*4));
+        break;
+
+    case EXTI8:
+    case EXTI9:
+    case EXTI10:
+    case EXTI11:
+        REG_SET_MASK(AFIO_EXTICR3, BIT_MASK_SHIFT(port, (channel-8)*4));
+        break;
+
+    case EXTI12:
+    case EXTI13:
+    case EXTI14:
+    case EXTI15:
+        REG_SET_MASK(AFIO_EXTICR4, BIT_MASK_SHIFT(port, (channel-12)*4));
+        break;
+    }
+
+    /* Unmask appropriate interrupt line  */
+    REG_SET_BIT(EXTI_IMR, channel);
+
+    /* Set trigger mode  */
+    switch (mode) {
+    case EXTI_RISING:
+        REG_SET_BIT(EXTI_RTSR, channel);
+        break;
+
+    case EXTI_FALLING:
+        REG_SET_BIT(EXTI_FTSR, channel);
+        break;
+
+    case EXTI_RISING_FALLING:
+        REG_SET_BIT(EXTI_RTSR, channel);
+        REG_SET_BIT(EXTI_FTSR, channel);
+        break;
+    }
+
+    /* Configure the enable interrupt bits for the NVIC  */
+    switch (channel) {
+    case EXTI0:
+    case EXTI1:
+    case EXTI2:
+    case EXTI3:
+    case EXTI4:
+        REG_SET(NVIC_ISER0, BIT(channel + 6));
+        break;
+
+    /* EXTI5-9 map to the same isr */
+    case EXTI5:
+    case EXTI6:
+    case EXTI7:
+    case EXTI8:
+    case EXTI9:
+        REG_SET(NVIC_ISER0, BIT(23));
+        break;
+
+    /* EXTI10-15 map to the same isr */
+    case EXTI10:
+    case EXTI11:
+    case EXTI12:
+    case EXTI13:
+    case EXTI14:
+    case EXTI15:
+        REG_SET(NVIC_ISER1, BIT(8));
+        break;
+    }
+
+    /* Register the handler  */
+    exti_handlers[channel] = handler;
+}
+
+
+void exti_detach_interrupt(uint8_t channel) {
+    ASSERT(channel < NR_EXTI_CHANNELS);
+    ASSERT(EXTI0 == 0);
+    /* Is this interrupt actually on?  */
+    ASSERT((REG_GET(EXTI_IMR) >> channel) & 0x01);
+
+    /* Clear EXTI_IMR line  */
+    REG_CLEAR_BIT(EXTI_IMR, channel);
+
+    /* Clear triggers  */
+    REG_CLEAR_BIT(EXTI_FTSR, channel);
+    REG_CLEAR_BIT(EXTI_RTSR, channel);
+
+    /* Turn off the associated interrupt */
+    switch (channel) {
+    case EXTI0:
+    case EXTI1:
+    case EXTI2:
+    case EXTI3:
+    case EXTI4:
+        REG_SET(NVIC_ICER0, BIT(channel + 6));
+        break;
+    case EXTI5:
+    case EXTI6:
+    case EXTI7:
+    case EXTI8:
+    case EXTI9:
+        /* Are there any other channels enabled?
+         * If so, don't disable the interrupt handler */
+        if (GET_BITS(REG_GET(EXTI_IMR), 5, 9) == 0) {
+            REG_SET(NVIC_ICER0, BIT(23));
+        }
+        break;
+    case EXTI10:
+    case EXTI11:
+    case EXTI12:
+    case EXTI13:
+    case EXTI14:
+    case EXTI15:
+        /* Are there any other channels enabled?
+         * If so, don't disable the interrupt handler */
+        if (GET_BITS(REG_GET(EXTI_IMR), 10, 15) == 0) {
+            REG_SET(NVIC_ICER1, BIT(8));
+        }
+        break;
+    }
+
+    /* Clear handler function pointer  */
+    exti_handlers[channel] = 0;
+}
diff --git a/libmaple/exti.h b/libmaple/exti.h
new file mode 100644
index 0000000..c728454
--- /dev/null
+++ b/libmaple/exti.h
@@ -0,0 +1,152 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/18/09 02:35:33
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file exti.h
+ *
+ *  @brief External interrupt control prototypes and defines
+ */
+
+#ifndef _EXTI_H_
+#define _EXTI_H_
+
+#include <inttypes.h>
+/* Notes:
+ *
+ * To generate the interrupt, the interrupt line should be configured and
+ * enabled. This is done by programming the two trigger registers with the
+ * desired edge detection and by enabling the interrupt request by writing a
+ * '1' to the corresponding bit in the interrupt mask register.  When the
+ * selected edge occurs on the external interrupt line, an interrupt request is
+ * generated. The pending bit corresponding to the interrupt line is also set.
+ * This request is reset by writing a '1' in the pending register.
+ *
+ * Hardware interrupt selection:
+ * To configure the 20 lines as interrupt sources, use the following procedure:
+ * 1) Configure AFIO_EXTIICR[y] to select the source input for EXTIx external 
+ *    interrupt
+ * 2) Configure the mask bits of the 20 interrupt lines (EXTI_IMR)
+ * 3) Configure the trigger selection bits of the interrupt lines (EXTI_RTSR and EXTI_FTSR)
+ * 4) Configure the enable and mask bits that control the NVIC_IRQ channel mapped to the External
+ * Interrupt Controller (EXTI) so that an inerrupt coming from one of the 20 lines
+ * can be correctly acknowledged.
+ *
+ * AFIO clock must be on.
+ *
+ * RM0008, page 107: "PD0, PD1 cannot be used for external interrupt/event generation
+ * on 36, 48, 64-bin packages."
+ *
+ * ----------------------------------------------------------------------------
+ * Pin to EXTI Line Mappings:
+ * EXTI0          EXTI1          EXTI2           EXTI3             EXTI4
+ * ----------------------------------------------------------------------------
+ * D2/PA0         D3/PA1         D1/PA2          D0/A6/PA3         D10/A10/PA4
+ * D26/EXT7/PB0   D27/EXT8/PB1   D16/A2/PC2      D17/A3/PC3        D18/A4/PC4
+ * D14/A0/PC0     D15/PC1        D25/EXT5/PD2
+ *
+ * EXTI5          EXTI6          EXTI7           EXTI8             EXTI9
+ * ----------------------------------------------------------------------------
+ * D13/A13/PA5    D12/A12/PA6    D11/A11/PA7     D6/PA8            D7/PA9
+ * D4/PB5         D5/PB6         D9/PB7          D38/PB8           D23/EXT4/PB9
+ * D19/A5/PC5     D34/EXTI15/PC6 D35/EXT16/PC7   D36/PC8           D37/EXT18/PC9
+ *
+ * EXTI10         EXTI11         EXTI12          EXTI13            EXTI14
+ * ----------------------------------------------------------------------------
+ * D8/PA10        D29/EXT10/PB11 D30/EXTI1/PB12  D31/EXTI12/PB13   D32/EXT13/PB14
+ * D28/PB10                                      D20/EXTI1/PC13    D21/EXT2/PC14
+ * D25/PC10
+ *
+ * EXTI15
+ * ----------------------------------------------------------------------------
+ * D33/EXTI14/PB15
+ * D22/EXT3/PC15
+ *
+ *
+ * The 16 EXTI interrupts are mapped to 7 interrupt handlers.
+ *
+ * EXTI Lines to Interrupt Mapping:
+ * EXTI0 -> EXTI0
+ * EXTI1 -> EXTI1
+ * EXTI2 -> EXTI2
+ * EXTI3 -> EXTI3
+ * EXTI4 -> EXTI4
+ * EXTI[5-9] -> EXT9_5
+ * EXTI[10-15] -> EXT15_10
+ *
+ *
+ * */
+
+#define NR_EXTI_CHANNELS         16
+#define NR_EXTI_PORTS             4
+#define NR_EXTI_MODES             3
+
+#define EXTI_IMR        0x40010400                   // Interrupt mask register
+#define EXTI_EMR        (EXTI_IMR + 0x04)            // Event mask register
+#define EXTI_RTSR       (EXTI_IMR + 0x08)            // Rising trigger selection register
+#define EXTI_FTSR       (EXTI_IMR + 0x0C)            // Falling trigger selection register
+#define EXTI_SWIER      (EXTI_IMR + 0x10)            // Software interrupt event register
+#define EXTI_PR         (EXTI_IMR + 0x14)            // Pending register
+
+#define AFIO_EVCR       0x40010000
+#define AFIO_EXTICR1    (AFIO_EVCR + 0x08)
+#define AFIO_EXTICR2    (AFIO_EVCR + 0x0C)
+#define AFIO_EXTICR3    (AFIO_EVCR + 0x10)
+#define AFIO_EXTICR4    (AFIO_EVCR + 0x14)
+
+#define EXTI_RISING                     0
+#define EXTI_FALLING                    1
+#define EXTI_RISING_FALLING             2
+
+#define EXTI0  0
+#define EXTI1  1
+#define EXTI2  2
+#define EXTI3  3
+#define EXTI4  4
+#define EXTI5  5
+#define EXTI6  6
+#define EXTI7  7
+#define EXTI8  8
+#define EXTI9  9
+#define EXTI10 10
+#define EXTI11 11
+#define EXTI12 12
+#define EXTI13 13
+#define EXTI14 14
+#define EXTI15 15
+
+#define EXTI_CONFIG_PORTA 0
+#define EXTI_CONFIG_PORTB 1
+#define EXTI_CONFIG_PORTC 2
+#define EXTI_CONFIG_PORTD 3
+
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+void exti_attach_interrupt(uint8_t, uint8_t, voidFuncPtr, uint8_t);
+void exti_detach_interrupt(uint8_t);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+
+#endif
+
diff --git a/libmaple/gpio.c b/libmaple/gpio.c
new file mode 100644
index 0000000..facb514
--- /dev/null
+++ b/libmaple/gpio.c
@@ -0,0 +1,55 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/18/09 02:35:49
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file gpio.c
+ *
+ *  @brief GPIO initialization routine
+ */
+
+#include "libmaple.h"
+#include "stm32f10x_rcc.h"
+#include "gpio.h"
+
+void gpio_init(void) {
+   /* Turn on clocks for GPIO  */
+   RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA |
+                          RCC_APB2Periph_GPIOB |
+                          RCC_APB2Periph_GPIOC |
+                          RCC_APB2Periph_GPIOD |
+                          RCC_APB2Periph_AFIO,
+                          ENABLE);
+}
+
+void gpio_set_mode(GPIO_Port* port, uint8 gpio_pin, uint8 mode) {
+    uint32_t tmp;
+    uint32_t shift = POS(gpio_pin % 8);
+    GPIOReg CR;
+
+    ASSERT(port);
+    ASSERT(gpio_pin < 16);
+
+    CR = (gpio_pin < 8) ? &(port->CRL) : &(port->CRH);
+
+    tmp = *CR;
+    tmp &= POS_MASK(shift);
+    tmp |= mode << shift;
+
+    *CR = tmp;
+}
diff --git a/libmaple/gpio.h b/libmaple/gpio.h
new file mode 100644
index 0000000..5e7cf29
--- /dev/null
+++ b/libmaple/gpio.h
@@ -0,0 +1,97 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/18/09 02:36:01
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file gpio.h
+ *
+ *  @brief GPIO prototypes, defines, and inlined access functions
+ */
+
+#ifndef _GPIO_H
+#define _GPIO_H
+
+/* Each of the GPIO port bits can be in the following modes (STM32 138/995):
+ *      Input floating
+ *      Input pull-up
+ *      Input pull-down
+ *      Analog Input
+ *      Output open-drain
+ *      Output push-pull
+ *      Alternate function push-pull
+ *      Alternate function open-drain
+ *
+ * - After reset, the alternate functions are not active and IO prts
+ * are set to Input Floating mode */
+
+#define GPIOA_BASE               (GPIO_Port*)0x40010800
+#define GPIOB_BASE               (GPIO_Port*)0x40010C00
+#define GPIOC_BASE               (GPIO_Port*)0x40011000
+#define GPIOD_BASE               (GPIO_Port*)0x40011400
+
+/* Pin modes are set by [CNFx[1:0] : MODEx[1:0]] */
+#define GPIO_SPEED_50MHZ            (0x3) // Max output speed 50 MHz
+#define GPIO_MODE_OUTPUT_PP         ((0x00 << 2) | GPIO_SPEED_50MHZ)
+#define GPIO_MODE_OUTPUT_OD         ((0x01 << 2) | GPIO_SPEED_50MHZ)
+
+#define GPIO_MODE_AF_OUTPUT_PP      ((0x02 << 2) | GPIO_SPEED_50MHZ)
+#define GPIO_MODE_AF_OUTPUT_OD      ((0x03 << 2) | GPIO_SPEED_50MHZ)
+
+/* Note: mode bits must be set to zero for input mode  */
+#define GPIO_MODE_INPUT_ANALOG      (0x00 << 2)
+#define GPIO_MODE_INPUT_FLOATING    (0x01 << 2)
+#define GPIO_MODE_INPUT_PD          (0x02 << 2)
+#define GPIO_MODE_INPUT_PU          (0x02 << 2)
+
+typedef struct {
+    volatile uint32 CRL;      // Port configuration register low
+    volatile uint32 CRH;      // Port configuration register high
+    volatile uint32 IDR;      // Port input data register
+    volatile uint32 ODR;      // Port output data register
+    volatile uint32 BSRR;     // Port bit set/reset register
+    volatile uint32 BRR;      // Port bit reset register
+    volatile uint32 LCKR;     // Port configuration lock register
+} GPIO_Port;
+
+typedef volatile uint32* GPIOReg;
+
+#define POS_MASK(shift) (~(0xF << shift))
+#define POS(val)        (val << 2)
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+void gpio_init(void);
+void gpio_set_mode(GPIO_Port* port, uint8 gpio_pin, uint8 mode);
+
+static inline void gpio_write_bit(GPIO_Port *port, uint8 gpio_pin, uint8 val) {
+    if (val){
+        port->BSRR = BIT(gpio_pin);
+    } else {
+        port->BRR = BIT(gpio_pin);
+    }
+}
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+
+#endif
+
diff --git a/libmaple/libmaple.h b/libmaple/libmaple.h
new file mode 100644
index 0000000..dc9ffd2
--- /dev/null
+++ b/libmaple/libmaple.h
@@ -0,0 +1,33 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/19/09 02:37:22 EST
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file libmaple.h
+ *
+ *  @brief general include file for libmaple
+ */
+
+#ifndef _LIBMAPLE_H_
+#define _LIBMAPLE_H_
+
+#include "libmaple_types.h"
+#include "util.h"
+
+#endif
+
diff --git a/libmaple/libmaple_types.h b/libmaple/libmaple_types.h
new file mode 100644
index 0000000..b798587
--- /dev/null
+++ b/libmaple/libmaple_types.h
@@ -0,0 +1,42 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/19/09 02:35:14 EST
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file libmaple_types.h
+ *
+ *  @brief libmaple types
+ */
+
+#ifndef _LIBMAPLE_TYPES_H_
+#define _LIBMAPLE_TYPES_H_
+
+typedef unsigned char uint8;
+typedef unsigned short uint16;
+typedef unsigned int uint32;
+typedef unsigned long long uint64;
+
+typedef signed char int8;
+typedef short int16;
+typedef int int32;
+typedef long long int64;
+
+typedef void (*voidFuncPtr)(void);
+
+#endif
+
diff --git a/libmaple/nvic.c b/libmaple/nvic.c
new file mode 100644
index 0000000..9b8c84f
--- /dev/null
+++ b/libmaple/nvic.c
@@ -0,0 +1,59 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/18/09 02:36:19
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file nvic.c
+ *
+ *  @brief Nested interrupt controller routines
+ */
+
+#include "libmaple.h"
+#include "nvic.h"
+#include "systick.h"
+
+void nvic_disable_interrupts(void) {
+    /* Turn off all interrupts  */
+    REG_SET(NVIC_ICER0, 0xFFFFFFFF);
+    REG_SET(NVIC_ICER1, 0xFFFFFFFF);
+
+    /* Turn off systick exception  */
+    REG_CLEAR_BIT(SYSTICK_CSR, 0);
+}
+
+
+void nvic_set_vector_table(uint32_t *addr, uint32_t offset) {
+//    SCB->VTOR = NVIC_VectTab | (Offset & (u32)0x1FFFFF80);
+}
+
+
+/**
+ *  @brief turn on interrupt number n
+ *  @param[in] n interrupt number
+ */
+void nvic_enable_interrupt(uint32 n) {
+    if (n >= NVIC_NR_INTERRUPTS) {
+        return;
+    }
+
+    if (n < 32) {
+        REG_SET_BIT(NVIC_ISER0, n);
+    } else {
+        REG_SET_BIT(NVIC_ISER1, n - 32);
+    }
+}
diff --git a/libmaple/nvic.h b/libmaple/nvic.h
new file mode 100644
index 0000000..5908e9c
--- /dev/null
+++ b/libmaple/nvic.h
@@ -0,0 +1,67 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/18/09 02:36:47
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file nvic.h
+ *
+ *  @brief Nested interrupt controller defines and prototypes
+ */
+
+#ifndef _NVIC_H_
+#define _NVIC_H_
+
+#define NVIC_INT_USBHP      19
+#define NVIC_INT_USBLP      20
+#define NVIC_EXTI1_OFFSET   (NVIC_ISER0 + 0x07)
+#define NVIC_EXTI9_5_OFFSET (NVIC_ISER0 + 0x17)
+
+/* NVIC Interrupt Enable registers  */
+#define NVIC_ISER0          0xE000E100
+#define NVIC_ISER1          0xE000E104
+#define NVIC_ISER2          0xE000E108
+#define NVIC_ISER3          0xE000E10C
+
+/* NVIC Interrupt Clear registers  */
+#define NVIC_ICER0          0xE000E180
+#define NVIC_ICER1          0xE000E184
+#define NVIC_ICER2          0xE000E188
+#define NVIC_ICER3          0xE000E18C
+
+/* System control registers  */
+#define SCB_VTOR            0xE000ED08  // Vector table offset register
+
+#define NVIC_VectTab_RAM             ((u32)0x20000000)
+#define NVIC_VectTab_FLASH           ((u32)0x08000000)
+
+#define NVIC_NR_INTERRUPTS        60
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+void nvic_disable_interrupts(void);
+void nvic_enable_interrupt(uint32);
+
+#ifdef __cplusplus
+}
+#endif
+
+
+#endif
+
diff --git a/libmaple/stm32f10x_conf.h b/libmaple/stm32f10x_conf.h
new file mode 100644
index 0000000..ddd1833
--- /dev/null
+++ b/libmaple/stm32f10x_conf.h
@@ -0,0 +1,132 @@
+/******************** (C) COPYRIGHT 2008 STMicroelectronics ********************

+* File Name          : stm32f10x_conf.h

+* Author             : MCD Application Team

+* Version            : V2.0.2

+* Date               : 07/11/2008

+* Description        : Library configuration file.

+********************************************************************************

+* THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS

+* WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE TIME.

+* AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY DIRECT,

+* INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING FROM THE

+* CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE CODING

+* INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.

+*******************************************************************************/

+

+/* Define to prevent recursive inclusion -------------------------------------*/

+#ifndef __STM32F10x_CONF_H

+#define __STM32F10x_CONF_H

+

+/* Includes ------------------------------------------------------------------*/

+#include "stm32f10x_type.h"

+

+/* Exported types ------------------------------------------------------------*/

+/* Exported constants --------------------------------------------------------*/

+/* Uncomment the line below to compile the library in DEBUG mode, this will expanse

+   the "assert_param" macro in the firmware library code (see "Exported macro"

+   section below) */

+/* #define DEBUG    1*/

+

+/* Comment the line below to disable the specific peripheral inclusion */

+/************************************* ADC ************************************/

+//#define _ADC

+//#define _ADC1

+//#define _ADC2

+//#define _ADC3

+//#define _BKP 

+//#define _CAN

+//#define _CRC

+//#define _DAC

+//#define _DBGMCU

+//#define _DMA

+//#define _DMA1_Channel1

+//#define _DMA1_Channel2

+//#define _DMA1_Channel3

+//#define _DMA1_Channel4

+//#define _DMA1_Channel5

+//#define _DMA1_Channel6

+//#define _DMA1_Channel7

+//#define _DMA2_Channel1

+//#define _DMA2_Channel2

+//#define _DMA2_Channel3

+//#define _DMA2_Channel4

+//#define _DMA2_Channel5

+#define _EXTI

+#define _FLASH

+

+/* Uncomment the line below to enable FLASH program/erase/protections functions,

+   otherwise only FLASH configuration (latency, prefetch, half cycle) functions

+   are enabled */

+/* #define _FLASH_PROG */

+

+#if 0

+#define _FSMC

+#define _GPIO

+#define _GPIOA

+#define _GPIOB

+#define _GPIOC

+#define _GPIOD

+#define _GPIOE

+#define _GPIOF

+#define _GPIOG

+#define _I2C

+#define _I2C1

+#define _I2C2

+#define _IWDG

+#define _PWR

+#define _RTC

+#define _SDIO

+#define _SPI

+#define _SPI1

+#define _SPI2

+#define _SPI3

+#define _SysTick

+#define _TIM

+#define _TIM1

+#define _TIM2

+#define _TIM3

+#define _TIM4

+#define _TIM5

+#define _TIM6

+#define _TIM7

+#define _TIM8

+#define _USART

+#define _USART1

+#define _USART3

+#define _UART4

+#define _UART5

+#endif

+#define _USART2

+#define _NVIC

+#define _RCC

+#define _AFIO

+

+/************************************* WWDG ***********************************/

+#define _WWDG

+

+/* In the following line adjust the value of External High Speed oscillator (HSE)

+   used in your application */

+#define HSE_Value    ((u32)8000000) /* Value of the External oscillator in Hz*/

+

+/* Exported macro ------------------------------------------------------------*/

+#ifdef  DEBUG

+/*******************************************************************************

+* Macro Name     : assert_param

+* Description    : The assert_param macro is used for function's parameters check.

+*                  It is used only if the library is compiled in DEBUG mode. 

+* Input          : - expr: If expr is false, it calls assert_failed function

+*                    which reports the name of the source file and the source

+*                    line number of the call that failed. 

+*                    If expr is true, it returns no value.

+* Return         : None

+*******************************************************************************/ 

+  #define assert_param(expr) ((expr) ? (void)0 : assert_failed((u8 *)__FILE__, __LINE__))

+/* Exported functions ------------------------------------------------------- */

+  void assert_failed(u8* file, u32 line);

+#else

+  #define assert_param(expr) ((void)0)

+#endif /* DEBUG */

+

+#endif /* __STM32F10x_CONF_H */

+

+/******************* (C) COPYRIGHT 2008 STMicroelectronics *****END OF FILE****/

diff --git a/libmaple/stm32f10x_it.c b/libmaple/stm32f10x_it.c
new file mode 100644
index 0000000..70d3269
--- /dev/null
+++ b/libmaple/stm32f10x_it.c
@@ -0,0 +1,252 @@
+void NMIException(void) {

+}

+void HardFaultException(void) {

+  while (1) {

+  }

+}

+

+void MemManageException(void) {

+  while (1) {

+  }

+}

+

+void BusFaultException(void) {

+  while (1) {

+  }

+}

+

+void UsageFaultException(void) {

+  while (1) {

+  }

+}

+

+#if 0

+void DebugMonitor(void) {

+}

+

+void SVCHandler(void) {

+}

+

+void PendSVC(void) {

+}

+

+void WWDG_IRQHandler(void) {

+}

+

+void PVD_IRQHandler(void) {

+}

+

+void TAMPER_IRQHandler(void) {

+}

+

+void RTC_IRQHandler(void) {

+}

+

+void FLASH_IRQHandler(void) {

+}

+

+void RCC_IRQHandler(void) {

+}

+

+void DMA1_Channel1_IRQHandler(void) {

+}

+

+void DMA1_Channel2_IRQHandler(void) {

+}

+

+void DMA1_Channel3_IRQHandler(void) {

+}

+

+void DMA1_Channel4_IRQHandler(void) {

+}

+

+void DMA1_Channel5_IRQHandler(void) {

+}

+

+void DMA1_Channel6_IRQHandler(void) {

+}

+

+void DMA1_Channel7_IRQHandler(void) {

+}

+

+void ADC1_2_IRQHandler(void) {

+}

+

+void USB_HP_CAN_TX_IRQHandler(void) {

+}

+

+void USB_LP_CAN_RX0_IRQHandler(void) {

+}

+

+void CAN_RX1_IRQHandler(void) {

+}

+

+void CAN_SCE_IRQHandler(void) {

+}

+

+void TIM1_BRK_IRQHandler(void) {

+}

+

+void TIM1_UP_IRQHandler(void) {

+    while(1) {

+    }

+}

+

+void TIM1_TRG_COM_IRQHandler(void) {

+}

+

+void TIM1_CC_IRQHandler(void) {

+    while(1)

+        ;

+}

+

+void TIM2_IRQHandler(void) {

+}

+

+void TIM3_IRQHandler(void) {

+}

+

+void TIM4_IRQHandler(void) {

+}

+

+void I2C1_EV_IRQHandler(void) {

+}

+

+void I2C1_ER_IRQHandler(void) {

+}

+

+void I2C2_EV_IRQHandler(void) {

+}

+

+void I2C2_ER_IRQHandler(void) {

+}

+

+void SPI1_IRQHandler(void) {

+}

+

+void SPI2_IRQHandler(void) {

+}

+

+void USART1_IRQHandler(void) {

+#if 0

+  if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)

+  {

+    /* Read one byte from the receive data register */

+    RxBuffer[RxCounter++] = (USART_ReceiveData(USART1) & 0x7F);         

+

+    if(RxCounter == NbrOfDataToRead)

+    {

+      /* Disable the USART Receive interrupt */

+      USART_ITConfig(USART1, USART_IT_RXNE, DISABLE);

+    }

+  }

+

+  if(USART_GetITStatus(USART1, USART_IT_TXE) != RESET)

+  {   

+    /* Write one byte to the transmit data register */

+    USART_SendData(USART1, TxBuffer[TxCounter++]);                    

+

+    if(TxCounter == NbrOfDataToTransfer)

+    {

+      /* Disable the USART1 Transmit interrupt */

+      USART_ITConfig(USART1, USART_IT_TXE, DISABLE);

+    }    

+  }

+#endif

+}

+

+void USART2_IRQHandler(void) {

+#if 0

+  if(USART_GetITStatus(USART2, USART_IT_RXNE) != RESET)

+  {

+      /* Echo the character back  */

+      RxBuffer[0] = (USART_ReceiveData(USART2) & 0x7F);         

+      USART_SendData(USART2, RxBuffer[0]);

+  //  /* Read one byte from the receive data register */

+  //  RxBuffer[RxCounter++] = (USART_ReceiveData(USART2) & 0x7F);         

+

+  //  if(RxCounter == NbrOfDataToRead)

+  //  {

+  //    /* Disable the USART Receive interrupt */

+  //    USART_ITConfig(USART2, USART_IT_RXNE, DISABLE);

+  //  }

+  }

+

+#endif

+ 

+#if 0

+  if(USART_GetITStatus(USART2, USART_IT_TXE) != RESET)

+  {   

+    /* Write one byte to the transmit data register */

+    USART_SendData(USART2, 'Y');                    

+    TxCounter++;

+//    USART_SendData(USART2, TxBuffer[TxCounter++]);                    

+

+    if(TxCounter == NbrOfDataToTransfer) {

+      /* Disable the USART1 Transmit interrupt */

+      USART_ITConfig(USART2, USART_IT_TXE, DISABLE);

+    }

+  }

+#endif

+}

+

+void USART3_IRQHandler(void) {

+}

+

+void RTCAlarm_IRQHandler(void) {

+}

+

+void USBWakeUp_IRQHandler(void) {

+}

+

+void TIM8_BRK_IRQHandler(void) {

+}

+

+void TIM8_UP_IRQHandler(void) {

+}

+

+void TIM8_TRG_COM_IRQHandler(void) {

+}

+

+void TIM8_CC_IRQHandler(void) {

+}

+

+void ADC3_IRQHandler(void) {

+}

+

+void FSMC_IRQHandler(void) {

+}

+

+void SDIO_IRQHandler(void) {

+}

+

+void TIM5_IRQHandler(void) {

+}

+

+void SPI3_IRQHandler(void) {

+}

+

+void UART4_IRQHandler(void) {

+}

+

+void UART5_IRQHandler(void) {

+}

+

+void TIM6_IRQHandler(void) {

+}

+

+void TIM7_IRQHandler(void) {

+}

+

+void DMA2_Channel1_IRQHandler(void) {

+}

+

+void DMA2_Channel2_IRQHandler(void) {

+}

+

+void DMA2_Channel3_IRQHandler(void) {

+}

+

+void DMA2_Channel4_5_IRQHandler(void) {

+}

+#endif

diff --git a/libmaple/syscalls.c b/libmaple/syscalls.c
new file mode 100644
index 0000000..390cecd
--- /dev/null
+++ b/libmaple/syscalls.c
@@ -0,0 +1,157 @@
+#include "libmaple.h"
+#include <sys/stat.h>
+
+/* _end is set in the linker command file */
+extern caddr_t _end;
+
+/* just in case, most boards have at least some memory */
+#ifndef RAMSIZE
+#  define RAMSIZE             (caddr_t)0x50000
+#endif
+
+#define STACK_TOP 0x20000800
+
+void uart_send(const char*str);
+
+/*
+ * sbrk -- changes heap size size. Get nbytes more
+ *         RAM. We just increment a pointer in what's
+ *         left of memory on the board.
+ */
+caddr_t
+_sbrk(nbytes)
+int nbytes;
+{
+    static caddr_t heap_ptr = NULL;
+    caddr_t        base;
+
+    if (heap_ptr == NULL) {
+        heap_ptr = (caddr_t)&_end;
+    }
+
+    if ((STACK_TOP - (unsigned int)heap_ptr) >= 0) {
+        base = heap_ptr;
+        heap_ptr += nbytes;
+        return (base);
+    } else {
+        uart_send("heap full!\r\n");
+        return ((caddr_t)-1);
+    }
+}
+
+int _open(const char *path, int flags, ...)
+{
+    return 1;
+}
+
+int _close(int fd)
+{
+    return 0;
+}
+
+int _fstat(int fd, struct stat *st)
+{
+    st->st_mode = S_IFCHR;
+    return 0;
+}
+
+int _isatty(int fd)
+{
+    return 1;
+}
+
+int isatty(int fd)
+{
+    return 1;
+}
+
+int _lseek(int fd, off_t pos, int whence)
+{
+    return -1;
+}
+
+unsigned char getch(void)
+{
+//    while (!(USART2->SR & USART_FLAG_RXNE));
+//    return USART2->DR;
+    return 0;
+}
+
+
+int _read(int fd, char *buf, size_t cnt)
+{
+    *buf = getch();
+
+    return 1;
+}
+
+void putch(unsigned char c)
+{
+//    if (c == '\n') putch('\r');
+
+//    while (!(USART2->SR & USART_FLAG_TXE));
+//    USART2->DR = c;
+}
+
+void cgets(char *s, int bufsize)
+{
+    char *p;
+    int c;
+    int i;
+
+    for (i = 0; i < bufsize; i++) {
+        *(s+i) = 0;
+    }
+//    memset(s, 0, bufsize);
+
+    p = s;
+
+    for (p = s; p < s + bufsize-1;)
+    {
+        c = getch();
+        switch (c)
+        {
+        case '\r' :
+        case '\n' :
+            putch('\r');
+            putch('\n');
+            *p = '\n';
+            return;
+
+        case '\b' :
+            if (p > s)
+            {
+                *p-- = 0;
+                putch('\b');
+                putch(' ');
+                putch('\b');
+            }
+            break;
+
+        default :
+            putch(c);
+            *p++ = c;
+            break;
+        }
+    }
+    return;
+}
+
+int _write(int fd, const char *buf, size_t cnt)
+{
+    int i;
+//    uart_send("_write\r\n");
+
+    for (i = 0; i < cnt; i++)
+        putch(buf[i]);
+
+    return cnt;
+}
+
+/* Override fgets() in newlib with a version that does line editing */
+char *fgets(char *s, int bufsize, void *f)
+{
+//    uart_send("fgets\r\n");
+    cgets(s, bufsize);
+    return s;
+}
diff --git a/libmaple/systick.c b/libmaple/systick.c
new file mode 100644
index 0000000..47be69e
--- /dev/null
+++ b/libmaple/systick.c
@@ -0,0 +1,52 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/18/09 02:37:24
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file systick.c
+ *
+ *  @brief System timer interrupt handler and initialization routines
+ */
+
+#include "libmaple.h"
+#include "systick.h"
+
+#define MILLIS_INC 1
+
+volatile uint32_t systick_timer_millis = 0;
+
+void systick_init(void) {
+    /* Set the reload counter to tick every 1ms  */
+    REG_SET_MASK(SYSTICK_RELOAD, MAPLE_RELOAD_VAL);
+//    SYSTICK_RELOAD = MAPLE_RELOAD_VAL;
+
+    /* Clock the system timer with the core clock
+     * and turn it on, interrrupt every 1ms to keep track of millis()*/
+    REG_SET(SYSTICK_CSR, SYSTICK_SRC_HCLK |
+                         SYSTICK_ENABLE   |
+                         SYSTICK_TICKINT);
+//    SYSTICK_CSR = SYSTICK_SRC_HCLK |
+//                  SYSTICK_ENABLE   |
+//                  SYSTICK_TICKINT;
+}
+
+void SysTickHandler(void) {
+    systick_timer_millis++;
+}
+
+
diff --git a/libmaple/systick.h b/libmaple/systick.h
new file mode 100644
index 0000000..61789c4
--- /dev/null
+++ b/libmaple/systick.h
@@ -0,0 +1,62 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/18/09 02:37:37
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file systick.h
+ *
+ *  @brief Various system timer definitions
+ */
+
+#ifndef _SYSTICK_H_
+#define _SYSTICK_H_
+
+#include "libmaple.h"
+
+/* To the ARM technical manual... there's nearly nothing on the systick
+ * timer in the stm32 manual */
+
+#define SYSTICK_CSR       0xE000E010  // Control and status register
+#define SYSTICK_RELOAD    0xE000E014  // Reload value register
+#define SYSTICK_CNT       0xE000E018  // Current value register
+#define SYSTICK_CALIB     0xE000E01C  // Calibration value register
+
+#define SYSTICK_SRC_HCLK  BIT(2)    // Use core clock
+#define SYSTICK_TICKINT   BIT(1)    // Interrupt on systick countdown
+#define SYSTICK_ENABLE    BIT(0)    // Turn on the counter
+
+/* We use the systick timer to tick once
+ * every millisecond */
+#define MAPLE_RELOAD_VAL     72000
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+void systick_init(void);
+
+static inline uint32_t systick_get_count(void) {
+    return (uint32_t)*(volatile uint32*)SYSTICK_CNT;
+}
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif
+
diff --git a/libmaple/timers.c b/libmaple/timers.c
new file mode 100644
index 0000000..773ae36
--- /dev/null
+++ b/libmaple/timers.c
@@ -0,0 +1,192 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/18/09 02:37:54
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file timers.c
+ *
+ *  @brief General timer routines
+ */
+
+#include "libmaple.h"
+#include "stm32f10x_rcc.h"
+#include "timers.h"
+
+typedef struct {
+    volatile uint16_t CR1;
+    uint16_t  RESERVED0;
+    volatile uint16_t CR2;
+    uint16_t  RESERVED1;
+    volatile uint16_t SMCR;
+    uint16_t  RESERVED2;
+    volatile uint16_t DIER;
+    uint16_t  RESERVED3;
+    volatile uint16_t SR;
+    uint16_t  RESERVED4;
+    volatile uint16_t EGR;
+    uint16_t  RESERVED5;
+    volatile uint16_t CCMR1;
+    uint16_t  RESERVED6;
+    volatile uint16_t CCMR2;
+    uint16_t  RESERVED7;
+    volatile uint16_t CCER;
+    uint16_t  RESERVED8;
+    volatile uint16_t CNT;
+    uint16_t  RESERVED9;
+    volatile uint16_t PSC;
+    uint16_t  RESERVED10;
+    volatile uint16_t ARR;
+    uint16_t  RESERVED11;
+    volatile uint16_t RCR;
+    uint16_t  RESERVED12;
+    volatile uint16_t CCR1;
+    uint16_t  RESERVED13;
+    volatile uint16_t CCR2;
+    uint16_t  RESERVED14;
+    volatile uint16_t CCR3;
+    uint16_t  RESERVED15;
+    volatile uint16_t CCR4;
+    uint16_t  RESERVED16;
+    volatile uint16_t BDTR;   // Not used in general purpose timers
+    uint16_t  RESERVED17;     // Not used in general purpose timers
+    volatile uint16_t DCR;
+    uint16_t  RESERVED18;
+    volatile uint16_t DMAR;
+    uint16_t  RESERVED19;
+} Timer;
+
+void timer_init(uint8_t timer_num, uint16_t prescale) {
+    Timer *timer;
+    uint32_t is_advanced = 0;
+
+    ASSERT(timer_num > 0 && timer_num <= 4);
+
+    switch(timer_num) {
+    case 1:
+        timer = (Timer*)TIMER1_BASE;
+        RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
+        is_advanced = 1;
+        break;
+    case 2:
+        timer = (Timer*)TIMER2_BASE;
+        RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
+        break;
+    case 3:
+        timer = (Timer*)TIMER3_BASE;
+        RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
+        break;
+    case 4:
+        timer = (Timer*)TIMER4_BASE;
+        RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
+        break;
+    }
+
+    timer->CR1 = ARPE;        // No clock division
+                              // Do not buffer auto-reload preload
+                              // Edge aligned
+                              // Upcounter
+                              // Do not stop counter at update event
+                              // Update events enabled (etc, see bits [1:2])
+                              // Counter disabled for now
+
+    timer->PSC = prescale;    // Prescaling by prescale (duh)
+    timer->ARR = 0xFFFF;      // Max reload cont
+
+    /* initialize all the channels to 50% duty cycle,
+     * TODO: none of them actually get output unless the gpio pin
+     * is set, this will probably consume a bit more power but
+     * we'll worry about that later. */
+    timer->CCR1   = 0x8FFF;     // PWM start value
+    timer->CCMR1 |= 0x68;       // PWM mode 1, enable preload register.
+    timer->CCER  |= 0x001;      // enable ch
+
+    timer->CCR2   = 0x8FFF;     // PWM start value
+    timer->CCMR1 |= (0x68 << 8);// PWM mode 1, enable preload register.
+    timer->CCER  |= 0x010;      // enable ch
+
+    timer->CCR3   = 0x8FFF;     // PWM start value
+    timer->CCMR2 |= 0x68;       // PWM mode 1, enable preload register.
+    timer->CCER  |= 0x100;      // enable ch
+
+    timer->CCR4   = 0x8FFF;     // PWM start value
+    timer->CCMR2 |= (0x68 << 8);// PWM mode 1, enable preload register.
+    timer->CCER  |= 0x1000;      // enable ch
+
+    /* Advanced timer?  */
+    if (is_advanced) {
+        timer->BDTR = 0x8000;     // moe enable
+    }
+
+    timer->DIER = 0;          // disable update interrupt
+    timer->EGR  = 1;          // Initialize update event and shadow registers
+    timer->CR1  |= 1;         // Enable timer
+}
+
+void timers_disable(void) {
+    Timer *timer;
+    int i;
+    Timer *timers[4] = {
+        (Timer*)TIMER1_BASE,
+        (Timer*)TIMER2_BASE,
+        (Timer*)TIMER3_BASE,
+        (Timer*)TIMER4_BASE,
+    };
+
+    for (i = 0; i < 4; i++) {
+        timer = timers[i];
+        timer->CR1 = 0;
+        timer->CCER = 0;
+    }
+}
+
+void timers_disable_channel(uint8 timer_num, uint8 channel) {
+    Timer *timer;
+    switch (timer_num) {
+    case 1:
+        timer = (Timer*)TIMER1_BASE;
+        break;
+    case 2:
+        timer = (Timer*)TIMER2_BASE;
+        break;
+    case 3:
+        timer = (Timer*)TIMER3_BASE;
+        break;
+    case 4:
+        timer = (Timer*)TIMER4_BASE;
+        break;
+    default:
+        ASSERT(0);
+    }
+
+    switch (channel) {
+    case 1:
+        timer->CCER &= ~(0x1);
+        break;
+    case 2:
+        timer->CCER &= ~(0x10);
+        break;
+    case 3:
+        timer->CCER &= ~(0x100);
+        break;
+    case 4:
+        timer->CCER &= ~(0x1000);
+        break;
+    default:
+        ASSERT(0);
+    }
+}
diff --git a/libmaple/timers.h b/libmaple/timers.h
new file mode 100644
index 0000000..18b0afb
--- /dev/null
+++ b/libmaple/timers.h
@@ -0,0 +1,145 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/18/09 02:38:10
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file timers.h
+ *
+ *  @brief Timer prototypes and various definitions
+ */
+
+/* Note to self:
+ * The timer clock frequencies are automatically fixed by hardware.
+ * There are two cases:
+ *     1.  if the APB prescaler is 1, the timer clock frequencies are
+ *         set to the same frequency as that of the APB domain to which
+ *         the timers are connected.
+ *     2.  otherwise, they are set to twice (x2) the frequency of the
+ *         APB domain to which the timers are connected.
+ * See stm32 manual, 77/995
+ *
+ * hence, 72 mhz timers
+ * */
+
+/* Maple Timer channels:
+ * Timer        Maple Pin               STM32 Pin     Type
+ * TIM1_CH1     D6                      PA8           Advanced
+ * TIM1_CH2     D7                      PA9           Advanced
+ * TIM1_CH3     D8                      PA10          Advanced
+ *
+ * TIM2_CH1     D2                      PA0
+ * TIM2_CH2     D3                      PA1
+ * TIM2_CH3     D1                      PA2
+ * TIM2_CH4     D0                      PA3
+ *
+ * TIM3_CH1     D12                     PA6
+ * TIM3_CH2     D11                     PA7
+ * TIM3_CH3     EXT7                    PB0
+ * TIM3_CH4     EXT8                    PB1
+ *
+ * TIM4_CH1     EXT5                    PB6
+ * TIM4_CH1     EXT9                    PB7
+ * TIM4_CH1     EXT15                   PB8
+ * TIM4_CH1     EXT4                    PB9
+ *
+ * Not supported:
+ * TIM1_CH4    USBDM, not available     PA11          Advanced
+ * TIM1_CH1_N  EXT12                    PB13
+ * TIM1_CH2_N  EXT13                    PB14
+ * TIM1_CH3_N  EXT14                    PB15
+ * */
+
+/* I don't like the Arduino API for dealing with pin modes.
+ * How about...
+ *
+ * pinMode(digitalPin, PWM);
+ * pwmWrite(digitalPin) */
+
+
+#ifndef _TIMERS_H_
+#define _TIMERS_H_
+#include  <inttypes.h>
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+typedef volatile uint32_t* TimerCCR;
+
+#define TIMER1_BASE        0x40012C00
+#define TIMER2_BASE        0x40000000
+#define TIMER3_BASE        0x40000400
+#define TIMER4_BASE        0x40000800
+
+#define ARPE               BIT(7)                // Auto-reload preload enable
+#define NOT_A_TIMER        0
+
+#define TIMER1_CH1_CCR     (TimerCCR)(TIMER1_BASE + 0x34)
+#define TIMER1_CH2_CCR     (TimerCCR)(TIMER1_BASE + 0x38)
+#define TIMER1_CH3_CCR     (TimerCCR)(TIMER1_BASE + 0x3C)
+#define TIMER1_CH4_CCR     (TimerCCR)(TIMER1_BASE + 0x40)
+
+#define TIMER2_CH1_CCR     (TimerCCR)(TIMER2_BASE + 0x34)
+#define TIMER2_CH2_CCR     (TimerCCR)(TIMER2_BASE + 0x38)
+#define TIMER2_CH3_CCR     (TimerCCR)(TIMER2_BASE + 0x3C)
+#define TIMER2_CH4_CCR     (TimerCCR)(TIMER2_BASE + 0x40)
+
+#define TIMER3_CH1_CCR     (TimerCCR)(TIMER3_BASE + 0x34)
+#define TIMER3_CH2_CCR     (TimerCCR)(TIMER3_BASE + 0x38)
+#define TIMER3_CH3_CCR     (TimerCCR)(TIMER3_BASE + 0x3C)
+#define TIMER3_CH4_CCR     (TimerCCR)(TIMER3_BASE + 0x40)
+
+#define TIMER4_CH1_CCR     (TimerCCR)(TIMER4_BASE + 0x34)
+#define TIMER4_CH2_CCR     (TimerCCR)(TIMER4_BASE + 0x38)
+#define TIMER4_CH3_CCR     (TimerCCR)(TIMER4_BASE + 0x3C)
+#define TIMER4_CH4_CCR     (TimerCCR)(TIMER4_BASE + 0x40)
+
+
+/* Turn on timer with prescale as the divisor
+ * void timer_init(uint32_t timer, uint16_t prescale)
+ *      timer     ->  {1-4}
+ *      prescale  ->  {1-65535}
+ * */
+void timer_init(uint8_t, uint16_t);
+void timers_disable(void);
+void timers_disable_channel(uint8, uint8);
+
+/* Turn on PWM with duty_cycle on the specified channel in timer.
+ * This function takes in a pointer to the corresponding CCR
+ * register for the pin cause it saves pwmWrite() a couple of
+ * cycles.
+ *
+ * void timer_pwm(uint8_t channel, uint8_t duty_cycle);
+ *      channel    -> {TIMERx_CHn_CCR}
+ *      duty_cycle -> {0-65535}
+ *
+ * PRECONDITIONS:
+ *      pin has been set to alternate function output
+ *      timer has been initialized
+ */
+static inline void timer_pwm_write_ccr(TimerCCR CCR, uint16_t duty_cycle) {
+    *CCR = duty_cycle;
+}
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+
+#endif
+
diff --git a/libmaple/usart.c b/libmaple/usart.c
new file mode 100644
index 0000000..9987641
--- /dev/null
+++ b/libmaple/usart.c
@@ -0,0 +1,345 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/18/09 02:38:26
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file usart.c
+ *
+ *  @brief USART control routines
+ */
+
+#include "libmaple.h"
+#include "stm32f10x_rcc.h"
+#include "usart.h"
+#include "nvic.h"
+
+#define USART1_BASE         0x40013800
+#define USART2_BASE         0x40004400
+#define USART3_BASE         0x40004800
+
+#define USART_UE            BIT(13)
+#define USART_M             BIT(12)
+#define USART_TE            BIT(3)
+#define USART_RE            BIT(2)
+#define USART_RXNEIE        BIT(5)       // read data register not empty interrupt enable
+#define USART_TXE           BIT(7)
+#define USART_TC            BIT(6)
+
+#define USART_STOP_BITS_1   BIT_MASK_SHIFT(0b0, 12)
+#define USART_STOP_BITS_05  BIT_MASK_SHIFT(0b01, 12)
+#define USART_STOP_BITS_2   BIT_MASK_SHIFT(0b02, 12)
+#define USART_STOP_BITS_15  BIT_MASK_SHIFT(0b02, 12)
+
+#define USART1_CLK          72000000UL
+#define USART2_CLK          36000000UL
+#define USART3_CLK          36000000UL
+
+#define USART_RECV_BUF_SIZE 64
+
+/* Ring buffer notes:
+ * The buffer is empty when head == tail.
+ * The buffer is full when the head is one byte in front of the tail
+ * The total buffer size must be a power of two
+ * Note, one byte is necessarily left free with this scheme */
+typedef struct usart_ring_buf {
+    uint32 head;
+    uint32 tail;
+    uint8 buf[USART_RECV_BUF_SIZE];
+} usart_ring_buf;
+
+static usart_ring_buf ring_buf1;
+static usart_ring_buf ring_buf2;
+static usart_ring_buf ring_buf3;
+
+typedef struct usart_port {
+    volatile uint32 SR;       // Status register
+    volatile uint32 DR;       // Data register
+    volatile uint32 BRR;      // Baud rate register
+    volatile uint32 CR1;      // Control register 1
+    volatile uint32 CR2;      // Control register 2
+    volatile uint32 CR3;      // Control register 3
+    volatile uint32 GTPR;     // Guard time and prescaler register
+} usart_port;
+
+void USART1_IRQHandler(void) {
+    /* Read the data  */
+    ring_buf1.buf[ring_buf1.tail++] = (uint8_t)(((usart_port*)(USART1_BASE))->DR);
+    ring_buf1.tail %= USART_RECV_BUF_SIZE;
+}
+
+/* Don't overrun your buffer, seriously  */
+void USART2_IRQHandler(void) {
+    /* Read the data  */
+    ring_buf2.buf[ring_buf2.tail++] = (uint8_t)(((usart_port*)(USART2_BASE))->DR);
+    ring_buf2.tail %= USART_RECV_BUF_SIZE;
+}
+/* Don't overrun your buffer, seriously  */
+void USART3_IRQHandler(void) {
+    /* Read the data  */
+    ring_buf3.buf[ring_buf3.tail++] = (uint8_t)(((usart_port*)(USART3_BASE))->DR);
+    ring_buf3.tail %= USART_RECV_BUF_SIZE;
+}
+
+/**
+ *  @brief Enable a USART in single buffer transmission mode, multibuffer
+ *  receiver mode.
+ *
+ *  @param usart_num USART to be initialized
+ *  @param baud Baud rate to be set at
+ *  @param recvBuf buf buffer for receiver
+ *  @param len size of recvBuf
+ *
+ *  @sideeffect Turns on the specified USART
+ */
+void usart_init(uint8 usart_num, uint32 baud) {
+    ASSERT((usart_num <= NR_USARTS) && (usart_num > 0));
+    ASSERT(baud && (baud < USART_MAX_BAUD));
+
+    usart_port *port;
+    usart_ring_buf *ring_buf;
+
+    uint32 clk_speed;
+    uint32 integer_part;
+    uint32 fractional_part;
+    uint32 tmp;
+
+    switch (usart_num) {
+    case 1:
+        port = (usart_port*)USART1_BASE;
+        ring_buf = &ring_buf1;
+        clk_speed = USART1_CLK;
+        RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
+        REG_SET(NVIC_ISER1, BIT(5));
+        break;
+    case 2:
+        port = (usart_port*)USART2_BASE;
+        ring_buf = &ring_buf2;
+        clk_speed = USART2_CLK;
+        RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
+        REG_SET(NVIC_ISER1, BIT(6));
+        break;
+    case 3:
+        port = (usart_port*)USART3_BASE;
+        ring_buf = &ring_buf3;
+        clk_speed = USART3_CLK;
+        RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);
+        REG_SET(NVIC_ISER1, BIT(7));
+        break;
+    default:
+        /* should never get here  */
+        ASSERT(0);
+    }
+
+    /* Initialize ring buffer  */
+    ring_buf->head = 0;
+    ring_buf->tail = 0;
+
+    /* Set baud rate  */
+    integer_part = ((25 * clk_speed) / (4 * baud));
+    tmp = (integer_part / 100) << 4;
+
+    fractional_part = integer_part - (100 * (tmp >> 4));
+    tmp |= (((fractional_part * 16) + 50) / 100) & ((uint8)0x0F);
+
+    port->BRR = (uint16_t)tmp;
+
+    port->CR1 = USART_TE          |    // transmitter enable
+                USART_RE          |    // receiver enable
+                USART_RXNEIE;          // receive interrupt enable
+
+
+    /* Enable the USART and set mode to 8n1 */
+    port->CR1 |= USART_UE;
+}
+
+
+/**
+ *  @brief Turn off a USART.
+ *
+ *  @param USART to be disabled
+ *
+ *  @sideeffect Turns off the specified USART
+ */
+void usart_disable(uint8 usart_num) {
+    ASSERT((usart_num <= NR_USARTS) && (usart_num > 0));
+    usart_port *port;
+
+    switch (usart_num) {
+    case 1:
+        port = (usart_port*)USART1_BASE;
+        break;
+    case 2:
+        port = (usart_port*)USART2_BASE;
+        break;
+    case 3:
+        port = (usart_port*)USART3_BASE;
+        break;
+    default:
+        /* should never get here  */
+        ASSERT(0);
+    }
+
+    /* Is this usart enabled?  */
+    if (!(port->SR & USART_UE))
+        return;
+
+    /* TC bit must be high before disabling the usart  */
+    while ((port->SR & USART_TC) == 0)
+        ;
+
+    /* Disable UE */
+    port->CR1 = 0;
+}
+
+
+/**
+ *  @brief Print a null terminated string to the specified USART
+ *
+ *  @param[in] usart_num USART to send on
+ *  @param[in] str String to send
+ */
+void usart_putstr(uint8 usart_num, const char* str) {
+    ASSERT((usart_num <= NR_USARTS) && (usart_num > 0));
+    char ch;
+
+    while((ch = *(str++)) != '\0') {
+        usart_putc(usart_num, ch);
+    }
+}
+
+/**
+ *  @brief Print an unsigned integer to the specified usart
+ *
+ *  @param[in] usart_num usart to send on
+ *  @param[in] val number to print
+ */
+void usart_putudec(uint8 usart_num, uint32 val) {
+    ASSERT((usart_num <= NR_USARTS) && (usart_num > 0));
+    char digits[12];
+    int i;
+
+    i = 0;
+    do {
+        digits[i++] = val % 10 + '0';
+        val /= 10;
+    } while (val > 0);
+    while (--i >= 0) {
+        usart_putc(usart_num, digits[i]);
+    }
+
+}
+
+
+/**
+ *  @brief Return one character from the receive buffer. Assumes
+ *  that there is data available.
+ *
+ *  @param[in] usart_num number of the usart to read from
+ *
+ *  @return character from ring buffer
+ *
+ *  @sideeffect may update the head pointer of the recv buffer
+ */
+uint8 usart_getc(uint8 usart_num) {
+    uint8 ch;
+    usart_ring_buf *rb;
+
+    switch (usart_num) {
+    case 1:
+        rb = &ring_buf1;
+        break;
+    case 2:
+        rb = &ring_buf2;
+        break;
+    case 3:
+        rb = &ring_buf3;
+        break;
+    default:
+        ASSERT(0);
+    }
+
+    /* Make sure there's actually data to be read  */
+    ASSERT(rb->head != rb->tail);
+
+    /* Read the data and check for wraparound  */
+    ch = rb->buf[rb->head++];
+    rb->head %= USART_RECV_BUF_SIZE;
+
+    return ch;
+}
+
+uint32 usart_data_available(uint8 usart_num) {
+    usart_ring_buf *rb;
+
+    switch (usart_num) {
+    case 1:
+        rb = &ring_buf1;
+        break;
+    case 2:
+        rb = &ring_buf2;
+        break;
+    case 3:
+        rb = &ring_buf3;
+        break;
+    default:
+        ASSERT(0);
+    }
+
+    return rb->tail - rb->head;
+}
+
+
+
+/**
+ *  @brief Output a byte out the uart
+ *
+ *  @param[in] usart_num usart number to output on
+ *  @param[in] byte byte to send
+ *
+ */
+void usart_putc(uint8 usart_num, uint8 byte) {
+    ASSERT((usart_num <= NR_USARTS) && (usart_num > 0));
+    usart_port *port;
+
+    switch (usart_num) {
+    case 1:
+        port = (usart_port*)USART1_BASE;
+        break;
+    case 2:
+        port = (usart_port*)USART2_BASE;
+        break;
+    case 3:
+        port = (usart_port*)USART3_BASE;
+        break;
+    default:
+        /* Should never get here  */
+        ASSERT(0);
+    }
+
+//    if (ch == '\n') {
+//        usart_putc(usart_num, '\r');
+//    }
+
+    port->DR = byte;
+
+    /* Wait for transmission to complete  */
+    while ((port->SR & USART_TXE) == 0)
+        ;
+}
+
+
diff --git a/libmaple/usart.h b/libmaple/usart.h
new file mode 100644
index 0000000..b9efdd5
--- /dev/null
+++ b/libmaple/usart.h
@@ -0,0 +1,53 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/18/09 02:38:35
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file usart.h
+ *
+ *  @brief USART Definitions
+ */
+
+#ifndef _USART_H_
+#define _USART_H_
+
+#define NR_USARTS           0x3
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+#define USART_MAX_BAUD      225000
+
+void usart_init(uint8 usart_num, uint32 baud);
+void usart_disable(uint8 usart_num);
+
+void usart_putstr(uint8 usart_num, const char*);
+void usart_putudec(uint8 usart_num, uint32 val);
+void usart_putc(uint8 usart_num, uint8 ch);
+
+uint32 usart_data_available(uint8 usart_num);
+uint8 usart_getc(uint8 usart_num);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+
+#endif
+
diff --git a/libmaple/usb.c b/libmaple/usb.c
new file mode 100644
index 0000000..8c312f8
--- /dev/null
+++ b/libmaple/usb.c
@@ -0,0 +1,83 @@
+#include <inttypes.h>
+#include "usb.h"
+
+void usb_lpIRQHandler(void)
+{
+  typedef void (*funcPtr)(void);
+  
+  const uint32_t usbIsrAddr = *(uint32_t*)(USB_ISR_ADDR);
+  void (*ptrToUsbISR)(void) = (funcPtr) usbIsrAddr;
+  ptrToUsbISR();
+}
+
+void usb_userToPMABufferCopy(u8 *pbUsrBuf, u16 wPMABufAddr, u16 wNBytes)
+{
+  u32 n = (wNBytes + 1) >> 1;   /* n = (wNBytes + 1) / 2 */
+  u32 i, temp1, temp2;
+  u16 *pdwVal;
+  pdwVal = (u16 *)(wPMABufAddr * 2 + PMAAddr);
+  for (i = n; i != 0; i--)
+    {
+      temp1 = (u16) * pbUsrBuf;
+      pbUsrBuf++;
+      temp2 = temp1 | (u16) * pbUsrBuf << 8;
+      *pdwVal++ = temp2;
+      pdwVal++;
+      pbUsrBuf++;
+    }
+}
+
+void usb_PMAToUserBufferCopy(u8 *pbUsrBuf, u16 wPMABufAddr, u16 wNBytes)
+{
+  u32 n = (wNBytes + 1) >> 1;/* /2*/
+  u32 i;
+  u32 *pdwVal;
+  pdwVal = (u32 *)(wPMABufAddr * 2 + PMAAddr);
+  for (i = n; i != 0; i--)
+    {
+      *(u16*)pbUsrBuf++ = *pdwVal++;
+      pbUsrBuf++;
+    }
+}
+
+void usb_serialWriteStr(const char* outStr) {
+  u8 offset=0;
+  BootVectTable *bootVector = ((BootVectTable*)BOOTLOADER_VECT_TABLE);
+
+  while ((outStr[offset] != '\0')
+	 && (offset < USB_SERIAL_BUF_SIZE)) {
+    offset++;
+  }
+
+  delay(offset*1);
+
+  bootVector->serial_count_in = (u32*) &offset;
+  usb_userToPMABufferCopy((u8*)outStr,USB_SERIAL_ENDP_TXADDR,offset);
+  _SetEPTxCount(USB_SERIAL_ENDP_TX,offset);
+  _SetEPTxValid(USB_SERIAL_ENDP_TX);
+
+}
+
+void usb_serialWriteChar(unsigned char ch) {
+  BootVectTable *bootVector = ((BootVectTable*)BOOTLOADER_VECT_TABLE);
+
+  delay(1);
+
+  *(bootVector->serial_count_in) = 1;
+  usb_userToPMABufferCopy((u8*)(&ch),USB_SERIAL_ENDP_TXADDR,1);
+  _SetEPTxCount(USB_SERIAL_ENDP_TX,1);
+  _SetEPTxValid(USB_SERIAL_ENDP_TX);
+
+}
+
+uint8_t usb_serialGetRecvLen() {
+  uint8_t count_out =_GetEPRxCount(USB_SERIAL_ENDP_RX); 
+  return count_out;
+}
+
+void usb_copyRecvBuffer(unsigned char* dest, uint8_t len) {
+  ASSERT(len < USB_SERIAL_BUF_SIZE);
+  usb_PMAToUserBufferCopy((u8*)(dest),USB_SERIAL_ENDP_RXADDR,len);
+  _SetEPRxValid(USB_SERIAL_ENDP_RX);
+}
+
diff --git a/libmaple/usb.h b/libmaple/usb.h
new file mode 100644
index 0000000..3b7a971
--- /dev/null
+++ b/libmaple/usb.h
@@ -0,0 +1,32 @@
+#ifndef _USB_H_
+#define _USB_H_
+
+#include <inttypes.h>
+#include "util.h"
+#include "cortexm3_macro.h"
+#include "usb_regs.h"
+#include "bootVect.h"
+
+#define USB_ISR_ADDR              (0x08000090)
+#define USB_SERIAL_ENDP_TXADDR    ((uint32_t) 0xC0)
+#define USB_SERIAL_ENDP_RXADDR    ((uint32_t) 0x110)
+#define USB_SERIAL_ENDP_TX        ((uint16_t) 0x1)
+#define USB_SERIAL_ENDP_RX        ((uint16_t) 0x3)
+#define USB_SERIAL_BUF_SIZE       (0x40)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void usb_lpIRQHandler(void);  
+void usb_userToPMABufferCopy(u8  *pbUsrBuf,u16 wPMABufAddr,u16 wNBytes);
+void usb_PMAToUserBufferCopy(u8  *pbUsrBuf,u16 wPMABufAddr,u16 wNBytes);
+void usb_serialWriteStr(const char *outStr);
+void usb_serialWriteChar(unsigned char ch);
+uint8_t usb_serialGetRecvLen();
+void usb_copyRecvBuffer(unsigned char* dest, uint8_t len);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+#endif //_USB_H
diff --git a/libmaple/usb_regs.h b/libmaple/usb_regs.h
new file mode 100644
index 0000000..135d645
--- /dev/null
+++ b/libmaple/usb_regs.h
@@ -0,0 +1,555 @@
+/******************** (C) COPYRIGHT 2008 STMicroelectronics ********************

+* File Name          : usb_regs.h

+* Author             : MCD Application Team

+* Version            : V2.2.1

+* Date               : 09/22/2008

+* Description        : Interface prototype functions to USB cell registers

+********************************************************************************

+* THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS

+* WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE TIME.

+* AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY DIRECT,

+* INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING FROM THE

+* CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE CODING

+* INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.

+*******************************************************************************/

+

+/* Define to prevent recursive inclusion -------------------------------------*/

+#ifndef __USB_REGS_H

+#define __USB_REGS_H

+

+/* Includes ------------------------------------------------------------------*/

+/* Exported types ------------------------------------------------------------*/

+#include "stm32f10x_type.h"

+

+typedef enum _EP_DBUF_DIR

+{

+  /* double buffered endpoint direction */

+  EP_DBUF_ERR,

+  EP_DBUF_OUT,

+  EP_DBUF_IN

+}EP_DBUF_DIR;

+

+/* endpoint buffer number */

+enum EP_BUF_NUM

+{

+  EP_NOBUF,

+  EP_BUF0,

+  EP_BUF1

+};

+

+/* Exported constants --------------------------------------------------------*/

+#define RegBase  (0x40005C00L)  /* USB_IP Peripheral Registers base address */

+#define PMAAddr  (0x40006000L)  /* USB_IP Packet Memory Area base address   */

+

+/******************************************************************************/

+/*                         General registers                                  */

+/******************************************************************************/

+

+/* Control register */

+#define CNTR    ((volatile unsigned *)(RegBase + 0x40))

+/* Interrupt status register */

+#define ISTR    ((volatile unsigned *)(RegBase + 0x44))

+/* Frame number register */

+#define FNR     ((volatile unsigned *)(RegBase + 0x48))

+/* Device address register */

+#define DADDR   ((volatile unsigned *)(RegBase + 0x4C))

+/* Buffer Table address register */

+#define BTABLE  ((volatile unsigned *)(RegBase + 0x50))

+/******************************************************************************/

+/*                         Endpoint registers                                 */

+/******************************************************************************/

+#define EP0REG  ((volatile unsigned *)(RegBase)) /* endpoint 0 register address */

+

+/* endpoints enumeration */

+#define ENDP0   ((u8)0)

+#define ENDP1   ((u8)1)

+#define ENDP2   ((u8)2)

+#define ENDP3   ((u8)3)

+#define ENDP4   ((u8)4)

+#define ENDP5   ((u8)5)

+#define ENDP6   ((u8)6)

+#define ENDP7   ((u8)7)

+/******************************************************************************/

+/*                       ISTR interrupt events                                */

+/******************************************************************************/

+#define ISTR_CTR    (0x8000) /* Correct TRansfer (clear-only bit) */

+#define ISTR_DOVR   (0x4000) /* DMA OVeR/underrun (clear-only bit) */

+#define ISTR_ERR    (0x2000) /* ERRor (clear-only bit) */

+#define ISTR_WKUP   (0x1000) /* WaKe UP (clear-only bit) */

+#define ISTR_SUSP   (0x0800) /* SUSPend (clear-only bit) */

+#define ISTR_RESET  (0x0400) /* RESET (clear-only bit) */

+#define ISTR_SOF    (0x0200) /* Start Of Frame (clear-only bit) */

+#define ISTR_ESOF   (0x0100) /* Expected Start Of Frame (clear-only bit) */

+

+

+#define ISTR_DIR    (0x0010)  /* DIRection of transaction (read-only bit)  */

+#define ISTR_EP_ID  (0x000F)  /* EndPoint IDentifier (read-only bit)  */

+

+#define CLR_CTR    (~ISTR_CTR)   /* clear Correct TRansfer bit */

+#define CLR_DOVR   (~ISTR_DOVR)  /* clear DMA OVeR/underrun bit*/

+#define CLR_ERR    (~ISTR_ERR)   /* clear ERRor bit */

+#define CLR_WKUP   (~ISTR_WKUP)  /* clear WaKe UP bit     */

+#define CLR_SUSP   (~ISTR_SUSP)  /* clear SUSPend bit     */

+#define CLR_RESET  (~ISTR_RESET) /* clear RESET bit      */

+#define CLR_SOF    (~ISTR_SOF)   /* clear Start Of Frame bit   */

+#define CLR_ESOF   (~ISTR_ESOF)  /* clear Expected Start Of Frame bit */

+

+/******************************************************************************/

+/*             CNTR control register bits definitions                         */

+/******************************************************************************/

+#define CNTR_CTRM   (0x8000) /* Correct TRansfer Mask */

+#define CNTR_DOVRM  (0x4000) /* DMA OVeR/underrun Mask */

+#define CNTR_ERRM   (0x2000) /* ERRor Mask */

+#define CNTR_WKUPM  (0x1000) /* WaKe UP Mask */

+#define CNTR_SUSPM  (0x0800) /* SUSPend Mask */

+#define CNTR_RESETM (0x0400) /* RESET Mask   */

+#define CNTR_SOFM   (0x0200) /* Start Of Frame Mask */

+#define CNTR_ESOFM  (0x0100) /* Expected Start Of Frame Mask */

+

+

+#define CNTR_RESUME (0x0010) /* RESUME request */

+#define CNTR_FSUSP  (0x0008) /* Force SUSPend */

+#define CNTR_LPMODE (0x0004) /* Low-power MODE */

+#define CNTR_PDWN   (0x0002) /* Power DoWN */

+#define CNTR_FRES   (0x0001) /* Force USB RESet */

+

+/******************************************************************************/

+/*                FNR Frame Number Register bit definitions                   */

+/******************************************************************************/

+#define FNR_RXDP (0x8000) /* status of D+ data line */

+#define FNR_RXDM (0x4000) /* status of D- data line */

+#define FNR_LCK  (0x2000) /* LoCKed */

+#define FNR_LSOF (0x1800) /* Lost SOF */

+#define FNR_FN  (0x07FF) /* Frame Number */

+/******************************************************************************/

+/*               DADDR Device ADDRess bit definitions                         */

+/******************************************************************************/

+#define DADDR_EF (0x80)

+#define DADDR_ADD (0x7F)

+/******************************************************************************/

+/*                            Endpoint register                               */

+/******************************************************************************/

+/* bit positions */

+#define EP_CTR_RX      (0x8000) /* EndPoint Correct TRansfer RX */

+#define EP_DTOG_RX     (0x4000) /* EndPoint Data TOGGLE RX */

+#define EPRX_STAT      (0x3000) /* EndPoint RX STATus bit field */

+#define EP_SETUP       (0x0800) /* EndPoint SETUP */

+#define EP_T_FIELD     (0x0600) /* EndPoint TYPE */

+#define EP_KIND        (0x0100) /* EndPoint KIND */

+#define EP_CTR_TX      (0x0080) /* EndPoint Correct TRansfer TX */

+#define EP_DTOG_TX     (0x0040) /* EndPoint Data TOGGLE TX */

+#define EPTX_STAT      (0x0030) /* EndPoint TX STATus bit field */

+#define EPADDR_FIELD   (0x000F) /* EndPoint ADDRess FIELD */

+

+/* EndPoint REGister MASK (no toggle fields) */

+#define EPREG_MASK     (EP_CTR_RX|EP_SETUP|EP_T_FIELD|EP_KIND|EP_CTR_TX|EPADDR_FIELD)

+

+/* EP_TYPE[1:0] EndPoint TYPE */

+#define EP_TYPE_MASK   (0x0600) /* EndPoint TYPE Mask */

+#define EP_BULK        (0x0000) /* EndPoint BULK */

+#define EP_CONTROL     (0x0200) /* EndPoint CONTROL */

+#define EP_ISOCHRONOUS (0x0400) /* EndPoint ISOCHRONOUS */

+#define EP_INTERRUPT   (0x0600) /* EndPoint INTERRUPT */

+#define EP_T_MASK      (~EP_T_FIELD & EPREG_MASK)

+

+

+/* EP_KIND EndPoint KIND */

+#define EPKIND_MASK    (~EP_KIND & EPREG_MASK)

+

+/* STAT_TX[1:0] STATus for TX transfer */

+#define EP_TX_DIS      (0x0000) /* EndPoint TX DISabled */

+#define EP_TX_STALL    (0x0010) /* EndPoint TX STALLed */

+#define EP_TX_NAK      (0x0020) /* EndPoint TX NAKed */

+#define EP_TX_VALID    (0x0030) /* EndPoint TX VALID */

+#define EPTX_DTOG1     (0x0010) /* EndPoint TX Data TOGgle bit1 */

+#define EPTX_DTOG2     (0x0020) /* EndPoint TX Data TOGgle bit2 */

+#define EPTX_DTOGMASK  (EPTX_STAT|EPREG_MASK)

+

+/* STAT_RX[1:0] STATus for RX transfer */

+#define EP_RX_DIS      (0x0000) /* EndPoint RX DISabled */

+#define EP_RX_STALL    (0x1000) /* EndPoint RX STALLed */

+#define EP_RX_NAK      (0x2000) /* EndPoint RX NAKed */

+#define EP_RX_VALID    (0x3000) /* EndPoint RX VALID */

+#define EPRX_DTOG1     (0x1000) /* EndPoint RX Data TOGgle bit1 */

+#define EPRX_DTOG2     (0x2000) /* EndPoint RX Data TOGgle bit1 */

+#define EPRX_DTOGMASK  (EPRX_STAT|EPREG_MASK)

+/* Exported macro ------------------------------------------------------------*/

+/* SetCNTR */

+#define _SetCNTR(wRegValue)  (*CNTR   = (u16)wRegValue)

+

+/* SetISTR */

+#define _SetISTR(wRegValue)  (*ISTR   = (u16)wRegValue)

+

+/* SetDADDR */

+#define _SetDADDR(wRegValue) (*DADDR  = (u16)wRegValue)

+

+/* SetBTABLE */

+#define _SetBTABLE(wRegValue)(*BTABLE = (u16)(wRegValue & 0xFFF8))

+

+/* GetCNTR */

+#define _GetCNTR()   ((u16) *CNTR)

+

+/* GetISTR */

+#define _GetISTR()   ((u16) *ISTR)

+

+/* GetFNR */

+#define _GetFNR()    ((u16) *FNR)

+

+/* GetDADDR */

+#define _GetDADDR()  ((u16) *DADDR)

+

+/* GetBTABLE */

+#define _GetBTABLE() ((u16) *BTABLE)

+

+/* SetENDPOINT */

+#define _SetENDPOINT(bEpNum,wRegValue)  (*(EP0REG + bEpNum)= \

+    (u16)wRegValue)

+

+/* GetENDPOINT */

+#define _GetENDPOINT(bEpNum)        ((u16)(*(EP0REG + bEpNum)))

+

+/*******************************************************************************

+* Macro Name     : SetEPType

+* Description    : sets the type in the endpoint register(bits EP_TYPE[1:0])

+* Input          : bEpNum: Endpoint Number. 

+*                  wType

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _SetEPType(bEpNum,wType) (_SetENDPOINT(bEpNum,\

+                                  ((_GetENDPOINT(bEpNum) & EP_T_MASK) | wType)))

+

+/*******************************************************************************

+* Macro Name     : GetEPType

+* Description    : gets the type in the endpoint register(bits EP_TYPE[1:0]) 

+* Input          : bEpNum: Endpoint Number. 

+* Output         : None.

+* Return         : Endpoint Type

+*******************************************************************************/

+#define _GetEPType(bEpNum) (_GetENDPOINT(bEpNum) & EP_T_FIELD)

+

+/*******************************************************************************

+* Macro Name     : SetEPTxStatus

+* Description    : sets the status for tx transfer (bits STAT_TX[1:0]).

+* Input          : bEpNum: Endpoint Number. 

+*                  wState: new state

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _SetEPTxStatus(bEpNum,wState) {\

+    register u16 _wRegVal;       \

+    _wRegVal = _GetENDPOINT(bEpNum) & EPTX_DTOGMASK;\

+    /* toggle first bit ? */     \

+    if((EPTX_DTOG1 & wState)!= 0)      \

+      _wRegVal ^= EPTX_DTOG1;        \

+    /* toggle second bit ?  */         \

+    if((EPTX_DTOG2 & wState)!= 0)      \

+      _wRegVal ^= EPTX_DTOG2;        \

+    _SetENDPOINT(bEpNum, _wRegVal);    \

+  } /* _SetEPTxStatus */

+

+/*******************************************************************************

+* Macro Name     : SetEPRxStatus

+* Description    : sets the status for rx transfer (bits STAT_TX[1:0])

+* Input          : bEpNum: Endpoint Number. 

+*                  wState: new state.

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _SetEPRxStatus(bEpNum,wState) {\

+    register u16 _wRegVal;   \

+    \

+    _wRegVal = _GetENDPOINT(bEpNum) & EPRX_DTOGMASK;\

+    /* toggle first bit ? */  \

+    if((EPRX_DTOG1 & wState)!= 0) \

+      _wRegVal ^= EPRX_DTOG1;  \

+    /* toggle second bit ? */  \

+    if((EPRX_DTOG2 & wState)!= 0) \

+      _wRegVal ^= EPRX_DTOG2;  \

+    _SetENDPOINT(bEpNum, _wRegVal); \

+  } /* _SetEPRxStatus */

+/*******************************************************************************

+* Macro Name     : GetEPTxStatus / GetEPRxStatus 

+* Description    : gets the status for tx/rx transfer (bits STAT_TX[1:0]

+*                  /STAT_RX[1:0])

+* Input          : bEpNum: Endpoint Number. 

+* Output         : None.

+* Return         : status .

+*******************************************************************************/

+#define _GetEPTxStatus(bEpNum) ((u16)_GetENDPOINT(bEpNum) & EPTX_STAT)

+

+#define _GetEPRxStatus(bEpNum) ((u16)_GetENDPOINT(bEpNum) & EPRX_STAT)

+

+/*******************************************************************************

+* Macro Name     : SetEPTxValid / SetEPRxValid 

+* Description    : sets directly the VALID tx/rx-status into the enpoint register

+* Input          : bEpNum: Endpoint Number. 

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _SetEPTxValid(bEpNum)     (_SetEPTxStatus(bEpNum, EP_TX_VALID))

+

+#define _SetEPRxValid(bEpNum)     (_SetEPRxStatus(bEpNum, EP_RX_VALID))

+

+/*******************************************************************************

+* Macro Name     : GetTxStallStatus / GetRxStallStatus.

+* Description    : checks stall condition in an endpoint.

+* Input          : bEpNum: Endpoint Number. 

+* Output         : None.

+* Return         : TRUE = endpoint in stall condition.

+*******************************************************************************/

+#define _GetTxStallStatus(bEpNum) (_GetEPTxStatus(bEpNum) \

+                                   == EP_TX_STALL)

+#define _GetRxStallStatus(bEpNum) (_GetEPRxStatus(bEpNum) \

+                                   == EP_RX_STALL)

+

+/*******************************************************************************

+* Macro Name     : SetEP_KIND / ClearEP_KIND.

+* Description    : set & clear EP_KIND bit.

+* Input          : bEpNum: Endpoint Number. 

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _SetEP_KIND(bEpNum)    (_SetENDPOINT(bEpNum, \

+                                (_GetENDPOINT(bEpNum) | EP_KIND) & EPREG_MASK))

+#define _ClearEP_KIND(bEpNum)  (_SetENDPOINT(bEpNum, \

+                                (_GetENDPOINT(bEpNum) & EPKIND_MASK)))

+

+/*******************************************************************************

+* Macro Name     : Set_Status_Out / Clear_Status_Out.

+* Description    : Sets/clears directly STATUS_OUT bit in the endpoint register.

+* Input          : bEpNum: Endpoint Number. 

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _Set_Status_Out(bEpNum)    _SetEP_KIND(bEpNum)

+#define _Clear_Status_Out(bEpNum)  _ClearEP_KIND(bEpNum)

+

+/*******************************************************************************

+* Macro Name     : SetEPDoubleBuff / ClearEPDoubleBuff.

+* Description    : Sets/clears directly EP_KIND bit in the endpoint register.

+* Input          : bEpNum: Endpoint Number. 

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _SetEPDoubleBuff(bEpNum)   _SetEP_KIND(bEpNum)

+#define _ClearEPDoubleBuff(bEpNum) _ClearEP_KIND(bEpNum)

+

+/*******************************************************************************

+* Macro Name     : ClearEP_CTR_RX / ClearEP_CTR_TX.

+* Description    : Clears bit CTR_RX / CTR_TX in the endpoint register.

+* Input          : bEpNum: Endpoint Number. 

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _ClearEP_CTR_RX(bEpNum)   (_SetENDPOINT(bEpNum,\

+                                   _GetENDPOINT(bEpNum) & 0x7FFF & EPREG_MASK))

+#define _ClearEP_CTR_TX(bEpNum)   (_SetENDPOINT(bEpNum,\

+                                   _GetENDPOINT(bEpNum) & 0xFF7F & EPREG_MASK))

+

+/*******************************************************************************

+* Macro Name     : ToggleDTOG_RX / ToggleDTOG_TX .

+* Description    : Toggles DTOG_RX / DTOG_TX bit in the endpoint register.

+* Input          : bEpNum: Endpoint Number. 

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _ToggleDTOG_RX(bEpNum)    (_SetENDPOINT(bEpNum, \

+                                   EP_DTOG_RX | _GetENDPOINT(bEpNum) & EPREG_MASK))

+#define _ToggleDTOG_TX(bEpNum)    (_SetENDPOINT(bEpNum, \

+                                   EP_DTOG_TX | _GetENDPOINT(bEpNum) & EPREG_MASK))

+

+/*******************************************************************************

+* Macro Name     : ClearDTOG_RX / ClearDTOG_TX.

+* Description    : Clears DTOG_RX / DTOG_TX bit in the endpoint register.

+* Input          : bEpNum: Endpoint Number. 

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _ClearDTOG_RX(bEpNum)  if((_GetENDPOINT(bEpNum) & EP_DTOG_RX) != 0)\

+    _ToggleDTOG_RX(bEpNum)

+#define _ClearDTOG_TX(bEpNum)  if((_GetENDPOINT(bEpNum) & EP_DTOG_TX) != 0)\

+    _ToggleDTOG_TX(bEpNum)

+/*******************************************************************************

+* Macro Name     : SetEPAddress.

+* Description    : Sets address in an endpoint register.

+* Input          : bEpNum: Endpoint Number.

+*                  bAddr: Address. 

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _SetEPAddress(bEpNum,bAddr) _SetENDPOINT(bEpNum,\

+    _GetENDPOINT(bEpNum) & EPREG_MASK | bAddr)

+

+/*******************************************************************************

+* Macro Name     : GetEPAddress.

+* Description    : Gets address in an endpoint register.

+* Input          : bEpNum: Endpoint Number.

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _GetEPAddress(bEpNum) ((u8)(_GetENDPOINT(bEpNum) & EPADDR_FIELD))

+

+#define _pEPTxAddr(bEpNum) ((u32 *)((_GetBTABLE()+bEpNum*8  )*2 + PMAAddr))

+#define _pEPTxCount(bEpNum) ((u32 *)((_GetBTABLE()+bEpNum*8+2)*2 + PMAAddr))

+#define _pEPRxAddr(bEpNum) ((u32 *)((_GetBTABLE()+bEpNum*8+4)*2 + PMAAddr))

+#define _pEPRxCount(bEpNum) ((u32 *)((_GetBTABLE()+bEpNum*8+6)*2 + PMAAddr))

+

+/*******************************************************************************

+* Macro Name     : SetEPTxAddr / SetEPRxAddr.

+* Description    : sets address of the tx/rx buffer.

+* Input          : bEpNum: Endpoint Number.

+*                  wAddr: address to be set (must be word aligned).

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _SetEPTxAddr(bEpNum,wAddr) (*_pEPTxAddr(bEpNum) = ((wAddr >> 1) << 1))

+#define _SetEPRxAddr(bEpNum,wAddr) (*_pEPRxAddr(bEpNum) = ((wAddr >> 1) << 1))

+

+/*******************************************************************************

+* Macro Name     : GetEPTxAddr / GetEPRxAddr.

+* Description    : Gets address of the tx/rx buffer.

+* Input          : bEpNum: Endpoint Number.

+* Output         : None.

+* Return         : address of the buffer.

+*******************************************************************************/

+#define _GetEPTxAddr(bEpNum) ((u16)*_pEPTxAddr(bEpNum))

+#define _GetEPRxAddr(bEpNum) ((u16)*_pEPRxAddr(bEpNum))

+

+/*******************************************************************************

+* Macro Name     : SetEPCountRxReg.

+* Description    : Sets counter of rx buffer with no. of blocks.

+* Input          : pdwReg: pointer to counter.

+*                  wCount: Counter.

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _BlocksOf32(dwReg,wCount,wNBlocks) {\

+    wNBlocks = wCount >> 5;\

+    if((wCount & 0x1f) == 0)\

+      wNBlocks--;\

+    *pdwReg = (u32)((wNBlocks << 10) | 0x8000);\

+  }/* _BlocksOf32 */

+

+#define _BlocksOf2(dwReg,wCount,wNBlocks) {\

+    wNBlocks = wCount >> 1;\

+    if((wCount & 0x1) != 0)\

+      wNBlocks++;\

+    *pdwReg = (u32)(wNBlocks << 10);\

+  }/* _BlocksOf2 */

+

+#define _SetEPCountRxReg(dwReg,wCount)  {\

+    u16 wNBlocks;\

+    if(wCount > 62){_BlocksOf32(dwReg,wCount,wNBlocks);}\

+    else {_BlocksOf2(dwReg,wCount,wNBlocks);}\

+  }/* _SetEPCountRxReg */

+

+

+

+#define _SetEPRxDblBuf0Count(bEpNum,wCount) {\

+    u32 *pdwReg = _pEPTxCount(bEpNum); \

+    _SetEPCountRxReg(pdwReg, wCount);\

+  }

+/*******************************************************************************

+* Macro Name     : SetEPTxCount / SetEPRxCount.

+* Description    : sets counter for the tx/rx buffer.

+* Input          : bEpNum: endpoint number.

+*                  wCount: Counter value.

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _SetEPTxCount(bEpNum,wCount) (*_pEPTxCount(bEpNum) = wCount)

+#define _SetEPRxCount(bEpNum,wCount) {\

+    u32 *pdwReg = _pEPRxCount(bEpNum); \

+    _SetEPCountRxReg(pdwReg, wCount);\

+  }

+/*******************************************************************************

+* Macro Name     : GetEPTxCount / GetEPRxCount.

+* Description    : gets counter of the tx buffer.

+* Input          : bEpNum: endpoint number.

+* Output         : None.

+* Return         : Counter value.

+*******************************************************************************/

+#define _GetEPTxCount(bEpNum)((u16)(*_pEPTxCount(bEpNum)) & 0x3ff)

+#define _GetEPRxCount(bEpNum)((u16)(*_pEPRxCount(bEpNum)) & 0x3ff)

+

+/*******************************************************************************

+* Macro Name     : SetEPDblBuf0Addr / SetEPDblBuf1Addr.

+* Description    : Sets buffer 0/1 address in a double buffer endpoint.

+* Input          : bEpNum: endpoint number.

+*                : wBuf0Addr: buffer 0 address.

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _SetEPDblBuf0Addr(bEpNum,wBuf0Addr) {_SetEPTxAddr(bEpNum, wBuf0Addr);}

+#define _SetEPDblBuf1Addr(bEpNum,wBuf1Addr) {_SetEPRxAddr(bEpNum, wBuf1Addr);}

+

+/*******************************************************************************

+* Macro Name     : SetEPDblBuffAddr.

+* Description    : Sets addresses in a double buffer endpoint.

+* Input          : bEpNum: endpoint number.

+*                : wBuf0Addr: buffer 0 address.

+*                : wBuf1Addr = buffer 1 address.

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _SetEPDblBuffAddr(bEpNum,wBuf0Addr,wBuf1Addr) { \

+    _SetEPDblBuf0Addr(bEpNum, wBuf0Addr);\

+    _SetEPDblBuf1Addr(bEpNum, wBuf1Addr);\

+  } /* _SetEPDblBuffAddr */

+

+/*******************************************************************************

+* Macro Name     : GetEPDblBuf0Addr / GetEPDblBuf1Addr.

+* Description    : Gets buffer 0/1 address of a double buffer endpoint.

+* Input          : bEpNum: endpoint number.

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _GetEPDblBuf0Addr(bEpNum) (_GetEPTxAddr(bEpNum))

+#define _GetEPDblBuf1Addr(bEpNum) (_GetEPRxAddr(bEpNum))

+

+/*******************************************************************************

+* Macro Name     : SetEPDblBuffCount / SetEPDblBuf0Count / SetEPDblBuf1Count.

+* Description    : Gets buffer 0/1 address of a double buffer endpoint.

+* Input          : bEpNum: endpoint number.

+*                : bDir: endpoint dir  EP_DBUF_OUT = OUT 

+*                                      EP_DBUF_IN  = IN 

+*                : wCount: Counter value    

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _SetEPDblBuf0Count(bEpNum, bDir, wCount)  { \

+    if(bDir == EP_DBUF_OUT)\

+      /* OUT endpoint */ \

+    {_SetEPRxDblBuf0Count(bEpNum,wCount);} \

+    else if(bDir == EP_DBUF_IN)\

+      /* IN endpoint */ \

+      *_pEPTxCount(bEpNum) = (u32)wCount;  \

+  } /* SetEPDblBuf0Count*/

+

+#define _SetEPDblBuf1Count(bEpNum, bDir, wCount)  { \

+    if(bDir == EP_DBUF_OUT)\

+      /* OUT endpoint */ \

+    {_SetEPRxCount(bEpNum,wCount);}\

+    else if(bDir == EP_DBUF_IN)\

+      /* IN endpoint */\

+      *_pEPRxCount(bEpNum) = (u32)wCount; \

+  } /* SetEPDblBuf1Count */

+

+#define _SetEPDblBuffCount(bEpNum, bDir, wCount) {\

+    _SetEPDblBuf0Count(bEpNum, bDir, wCount); \

+    _SetEPDblBuf1Count(bEpNum, bDir, wCount); \

+  } /* _SetEPDblBuffCount  */

+

+/*******************************************************************************

+* Macro Name     : GetEPDblBuf0Count / GetEPDblBuf1Count.

+* Description    : Gets buffer 0/1 rx/tx counter for double buffering.

+* Input          : bEpNum: endpoint number.

+* Output         : None.

+* Return         : None.

+*******************************************************************************/

+#define _GetEPDblBuf0Count(bEpNum) (_GetEPTxCount(bEpNum))

+#define _GetEPDblBuf1Count(bEpNum) (_GetEPRxCount(bEpNum))

+

+#endif

+/******************* (C) COPYRIGHT 2008 STMicroelectronics *****END OF FILE****/

diff --git a/libmaple/util.c b/libmaple/util.c
new file mode 100644
index 0000000..d323611
--- /dev/null
+++ b/libmaple/util.c
@@ -0,0 +1,103 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/18/09 02:38:44
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file util.h
+ *
+ *  @brief Utility procedures for debugging, mostly an error LED fade and
+ *  messages dumped over a uart for failed asserts.
+ */
+
+#include "libmaple.h"
+#include "usart.h"
+#include "gpio.h"
+#include "nvic.h"
+#include "adc.h"
+#include "timers.h"
+
+#define ERROR_LED_PORT         GPIOA_BASE
+#define ERROR_LED_PIN          5
+#define ERROR_USART_NUM        2
+#define ERROR_USART_BAUD       9600
+#define ERROR_TX_PIN           2
+#define ERROR_TX_PORT          GPIOA_BASE
+
+/* Error assert + fade */
+void _fail(const char* file, int line, const char* exp) {
+    int32_t  slope   = 1;
+    int32_t CC      = 0x0000;
+    int32_t TOP_CNT = 0x02FF;
+    int32_t i       = 0;
+
+    /* Turn off interrupts */
+    nvic_disable_interrupts();
+
+    /* Turn off timers  */
+    timers_disable();
+
+    /* Turn off ADC */
+    adc_disable();
+
+    /* Turn off all usarts  */
+    usart_disable(1);
+    usart_disable(2);
+    usart_disable(3);
+
+    /* Initialize the error usart */
+    gpio_set_mode(ERROR_TX_PORT, ERROR_TX_PIN, GPIO_MODE_AF_OUTPUT_PP);
+    usart_init(ERROR_USART_NUM, ERROR_USART_BAUD);
+
+    /* Print failed assert message  */
+    usart_putstr(ERROR_USART_NUM, "ERROR: FAILED ASSERT(");
+    usart_putstr(ERROR_USART_NUM, exp);
+    usart_putstr(ERROR_USART_NUM, "): ");
+    usart_putstr(ERROR_USART_NUM, file);
+    usart_putstr(ERROR_USART_NUM, ": ");
+    usart_putudec(ERROR_USART_NUM, line);
+    usart_putc(ERROR_USART_NUM, '\n');
+
+    /* Turn on the error LED  */
+    gpio_set_mode(ERROR_LED_PORT, ERROR_LED_PIN, GPIO_MODE_OUTPUT_PP);
+
+    /* Turn the USB interrupt back on so the bootloader keeps on functioning  */
+    nvic_enable_interrupt(NVIC_INT_USBHP);
+    nvic_enable_interrupt(NVIC_INT_USBLP);
+
+    /* Error fade  */
+    while (1) {
+        if (CC == TOP_CNT)  {
+            slope = -1;
+        } else if (CC == 0) {
+            slope = 1;
+        }
+
+        if (i == TOP_CNT)  {
+            CC += slope;
+            i = 0;
+        }
+
+        if (i < CC) {
+            gpio_write_bit(ERROR_LED_PORT, ERROR_LED_PIN, 1);
+        } else {
+            gpio_write_bit(ERROR_LED_PORT, ERROR_LED_PIN, 0);
+        }
+        i++;
+    }
+}
+
diff --git a/libmaple/util.h b/libmaple/util.h
new file mode 100644
index 0000000..e425cc0
--- /dev/null
+++ b/libmaple/util.h
@@ -0,0 +1,82 @@
+/* *****************************************************************************
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Created: 12/18/09 02:39:27
+ *  Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ *  @file util.h
+ *
+ *  @brief Various macros and utility procedures.
+ */
+
+/* Generally "useful" utility procedures  */
+#ifndef _UTIL_H_
+#define _UTIL_H_
+#include <inttypes.h>
+
+#define MAPLE_DEBUG 1
+
+#define BIT(shift)                     (1 << (shift))
+#define BIT_MASK_SHIFT(mask, shift)    ((mask) << (shift))
+
+/* Return bits m to n of x  */
+#define GET_BITS(x, m, n) ((((uint32_t)x) << (31 - (n))) >> ((31 - (n)) + (m)))
+
+/* Bit-banding macros  */
+#define BITBAND_SRAM_REF   0x20000000
+#define BITBAND_SRAM_BASE  0x22000000
+#define BITBAND_SRAM(a,b) ((BITBAND_SRAM_BASE + (a-BITBAND_SRAM_REF)*32 + (b*4)))  // Convert SRAM address
+#define BITBAND_PERI_REF   0x40000000
+#define BITBAND_PERI_BASE  0x42000000
+#define BITBAND_PERI(a,b) ((BITBAND_PERI_BASE + (a-BITBAND_PERI_REF)*32 + (b*4)))  // Convert PERI address
+
+#define COUNTFLAG *((volatile unsigned char*) (BITBAND_PERI(SYSTICK_CSR,2)))
+
+#define REG_SET(reg, val)               (*(volatile uint32_t*)(reg)  = (val))
+#define REG_SET_BIT(reg, bit)           (*(volatile uint32_t*)(reg) |= BIT(bit))
+#define REG_CLEAR_BIT(reg, bit)         (*(volatile uint32_t*)(reg) &= ~BIT(bit))
+#define REG_SET_MASK(reg, mask)         (*(volatile uint32_t*)(reg) |= (uint32_t)(mask))
+#define REG_CLEAR_MASK(reg, mask)       (*(volatile uint32_t*)(reg) &= (uint32_t)~(mask))
+
+#define REG_GET(reg)                    *(volatile uint32_t*)(reg)
+
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+void _fail(const char*, int, const char*);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+
+/* Assert for sanity checks, undefine MAPLE_DEBUG to compile
+ * out these checks */
+#if MAPLE_DEBUG
+#define ASSERT(exp)         \
+    if (exp)              \
+        {}                  \
+    else                    \
+        _fail(__FILE__, __LINE__, #exp)
+#else
+#define ASSERT(exp) (void)((0))
+#endif
+
+#endif
+