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authorPerry Hung <iperry@alum.mit.edu>2010-04-22 02:36:01 -0400
committerPerry Hung <iperry@alum.mit.edu>2010-04-24 03:53:22 -0400
commit17e0e5edde60e9bf2aa4d52173ad7d47d6d6da75 (patch)
tree9ca6bcbea7e3183c206f16d5012a6b1797597ce1 /libmaple
parentcb3284fad5347fc9622a170d6e3cd870fd9e2846 (diff)
downloadlibrambutan-17e0e5edde60e9bf2aa4d52173ad7d47d6d6da75.tar.gz
librambutan-17e0e5edde60e9bf2aa4d52173ad7d47d6d6da75.zip
Initial SPI Polling implementation.
Initial commit of a polling-based SPI driver. The driver is limited to synchronous, blocking sends and a 8-bit data frame format. Tested on SPI1 and SPI2. Other peripherals are temporarily disabled, and the rx function is untested until I find a good peripheral to test everything on.
Diffstat (limited to 'libmaple')
-rw-r--r--libmaple/libmaple_types.h2
-rw-r--r--libmaple/rcc.h4
-rw-r--r--libmaple/spi.c132
-rw-r--r--libmaple/spi.h106
4 files changed, 244 insertions, 0 deletions
diff --git a/libmaple/libmaple_types.h b/libmaple/libmaple_types.h
index ca98f6f..d49f95a 100644
--- a/libmaple/libmaple_types.h
+++ b/libmaple/libmaple_types.h
@@ -43,5 +43,7 @@ typedef long long int64;
typedef void (*voidFuncPtr)(void);
+#define __io volatile
+
#endif
diff --git a/libmaple/rcc.h b/libmaple/rcc.h
index 8f786ee..9973bca 100644
--- a/libmaple/rcc.h
+++ b/libmaple/rcc.h
@@ -100,6 +100,10 @@
#define RCC_APB1ENR_TIM4EN BIT(2)
#define RCC_APB1ENR_USART2EN BIT(17)
#define RCC_APB1ENR_USART3EN BIT(18)
+#define RCC_APB1ENR_SPI2EN BIT(14)
+
+#define rcc_enable_clk_spi1() __set_bits(RCC_APB2ENR, RCC_APB2ENR_SPI1EN)
+#define rcc_enable_clk_spi2() __set_bits(RCC_APB1ENR, RCC_APB1ENR_SPI2EN)
#define rcc_enable_clk_timer1() __set_bits(RCC_APB2ENR, RCC_APB2ENR_TIM1EN)
#define rcc_enable_clk_timer2() __set_bits(RCC_APB1ENR, RCC_APB1ENR_TIM2EN)
diff --git a/libmaple/spi.c b/libmaple/spi.c
new file mode 100644
index 0000000..5a77b03
--- /dev/null
+++ b/libmaple/spi.c
@@ -0,0 +1,132 @@
+/* *****************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2010 Perry Hung.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ * ****************************************************************************/
+
+/**
+ * @brief libmaple serial peripheral interface (SPI) definitions
+ *
+ * Initial implementation for the SPI interface.
+ *
+ * This driver implements only the bare essentials of a polling driver at the
+ * moment. Master mode only, 8-bit data frames, and polling.
+ *
+ * The caller is responsible for controlling the chip select line.
+ *
+ * TODO: interrupt based driver, DMA.
+ *
+ */
+
+#include "libmaple.h"
+#include "gpio.h"
+#include "rcc.h"
+#include "spi.h"
+
+typedef struct spi_dev {
+ SPI *base;
+ GPIO_Port *port;
+ uint8 sck_pin;
+ uint8 miso_pin;
+ uint8 mosi_pin;
+} spi_dev;
+
+static const spi_dev spi_dev1 = {
+ .base = (SPI*)SPI1_BASE,
+ .port = GPIOA_BASE,
+ .sck_pin = 5,
+ .miso_pin = 6,
+ .mosi_pin = 7
+};
+
+static const spi_dev spi_dev2 = {
+ .base = (SPI*)SPI2_BASE,
+ .port = GPIOB_BASE,
+ .sck_pin = 13,
+ .miso_pin = 14,
+ .mosi_pin = 15
+};
+
+static void spi_gpio_cfg(spi_dev *dev);
+
+/**
+ * @brief Initialize a spi peripheral
+ * @param spi_num which spi to turn on, SPI1 or SPI2?
+ * @param prescale prescale factor on the input clock.
+ * @param endian data frame format (LSBFIRST?)
+ * @param mode SPI mode number
+ */
+void spi_init(uint32 spi_num,
+ uint32 prescale,
+ uint32 endian,
+ uint32 mode) {
+ ASSERT(spi_num == 1 || spi_num == 2);
+ ASSERT(mode < 4);
+
+ SPI *spi;
+ uint32 cr1 = 0;
+
+ switch (spi_num) {
+ case 1:
+ /* limit to 18 mhz max speed */
+ ASSERT(prescale != CR1_BR_PRESCALE_2);
+ spi = (SPI*)SPI1_BASE;
+ rcc_enable_clk_spi1();
+ spi_gpio_cfg(&spi_dev1);
+ break;
+ case 2:
+ spi = (SPI*)SPI2_BASE;
+ rcc_enable_clk_spi2();
+ spi_gpio_cfg(&spi_dev2);
+ break;
+ }
+
+ cr1 = prescale | endian | mode | CR1_MSTR | CR1_SSI | CR1_SSM;
+ spi->CR1 = cr1;
+
+ /* Peripheral enable */
+ spi->CR1 |= CR1_SPE;
+}
+
+
+/**
+ * @brief SPI synchronous 8-bit write, blocking.
+ * @param spi_num which spi to send on
+ * @return data shifted back from the slave
+ */
+void spi_tx(uint32 spi_num, uint8 data) {
+ SPI *spi;
+
+ ASSERT(spi_num == 1 || spi_num == 2);
+
+ spi = (spi_num == 1) ? (SPI*)SPI1_BASE : (SPI*)SPI2_BASE;
+
+ spi->DR = data;
+
+ while (!(spi->SR & SR_TXE) || (spi->SR & SR_BSY))
+ ;
+}
+
+static void spi_gpio_cfg(spi_dev *dev) {
+ gpio_set_mode(dev->port, dev->sck_pin, GPIO_MODE_AF_OUTPUT_PP);
+ gpio_set_mode(dev->port, dev->miso_pin, GPIO_MODE_AF_OUTPUT_PP);
+ gpio_set_mode(dev->port, dev->mosi_pin, GPIO_MODE_AF_OUTPUT_PP);
+}
diff --git a/libmaple/spi.h b/libmaple/spi.h
new file mode 100644
index 0000000..457f39b
--- /dev/null
+++ b/libmaple/spi.h
@@ -0,0 +1,106 @@
+/* *****************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2010 Perry Hung.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ * ****************************************************************************/
+
+/**
+ * @brief libmaple serial peripheral interface (SPI) prototypes and declarations
+ */
+
+#ifndef _SPI_H_
+#define _SPI_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* peripheral addresses */
+#define SPI1_BASE 0x40013000
+#define SPI2_BASE 0x40003800
+
+/* baud rate prescaler bits */
+#define CR1_BR 0x00000038
+#define CR1_BR_PRESCALE_2 0x00000000
+#define CR1_BR_PRESCALE_4 0x00000008
+#define CR1_BR_PRESCALE_8 0x00000010
+#define CR1_BR_PRESCALE_16 0x00000018
+#define CR1_BR_PRESCALE_32 0x00000020
+#define CR1_BR_PRESCALE_64 0x00000028
+#define CR1_BR_PRESCALE_128 0x00000030
+#define CR1_BR_PRESCALE_256 0x00000038
+
+#define CR1_LSBFIRST BIT(7 // data frame format
+#define CR1_MSTR BIT(2) // master selection
+#define CR1_SSM BIT(9) // software slave management
+#define CR1_SSI BIT(8) // internal slave select
+#define CR1_SPE BIT(6) // peripheral enable
+
+/* Status register bits */
+#define SR_RXNE BIT(0) // rx buffer not empty
+#define SR_TXE BIT(1) // transmit buffer empty
+#define SR_BSY BIT(7) // busy flag
+
+typedef struct SPI {
+ __io uint16 CR1;
+ uint16 pad0;
+ __io uint8 CR2;
+ uint8 pad1[3];
+ __io uint8 SR;
+ uint8 pad2[3];
+ __io uint16 DR;
+ uint16 pad3;
+ __io uint16 CRCPR;
+ uint16 pad4;
+ __io uint16 RXCRCR;
+ uint16 pad5;
+ __io uint16 TXCRCR;
+ uint16 pad6;
+} SPI;
+
+enum {
+ SPI_MSBFIRST = 0,
+ SPI_LSBFIRST = BIT(7),
+};
+
+enum {
+ SPI_PRESCALE_2 = (0x0 << 3),
+ SPI_PRESCALE_4 = (0x1 << 3),
+ SPI_PRESCALE_8 = (0x2 << 3),
+ SPI_PRESCALE_16 = (0x3 << 3),
+ SPI_PRESCALE_32 = (0x4 << 3),
+ SPI_PRESCALE_64 = (0x5 << 3),
+ SPI_PRESCALE_128 = (0x6 << 3),
+ SPI_PRESCALE_256 = (0x7 << 3)
+};
+
+void spi_init(uint32 spi_num,
+ uint32 prescale,
+ uint32 endian,
+ uint32 mode);
+void spi_tx(uint32 spi_num, uint8 data);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+