basic working dac implementation

6 files changed, 264 insertions, 0 deletions

diff --git a/examples/test-dac.cpp b/examples/test-dac.cpp
new file mode 100644
index 0000000..65496f4
--- /dev/null
+++ b/examples/test-dac.cpp
@@ -0,0 +1,53 @@
+

+#include "wirish.h"

+#include "fsmc.h"

+#include "rcc.h"

+#include "gpio.h"

+#include "dac.h"

+

+#define LED_PIN  23 // hack for maple native

+#define DISC_PIN 14 // hack for USB on native

+

+int toggle = 0;

+uint16 count = 0;

+

+void setup() {

+

+   pinMode(LED_PIN, OUTPUT);

+   pinMode(DISC_PIN, OUTPUT);

+   digitalWrite(DISC_PIN,1);

+   digitalWrite(LED_PIN,1);

+

+   Serial1.begin(9600);

+   Serial1.println("Hello World!");

+

+   Serial1.print("Init... ");

+   dac_init();

+   Serial1.println("Done.");

+}

+

+void loop() {

+   digitalWrite(LED_PIN, toggle);

+   toggle ^= 1;

+   delay(100);

+

+   count += 100;

+

+   if(count > 4095) {

+      count = 0;

+   }

+

+   dac_write(1, 2048);

+   dac_write(2, count);

+}

+

+int main(void) {

+   init();

+   setup();

+

+   while (1) {

+      loop();

+   }

+   return 0;

+}

+

diff --git a/libmaple/dac.c b/libmaple/dac.c
new file mode 100644
index 0000000..b9c7d63
--- /dev/null
+++ b/libmaple/dac.c
@@ -0,0 +1,67 @@
+
+/* *****************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2010 Bryan Newbold.
+ *
+ * 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.
+ * ****************************************************************************/
+
+#include "libmaple.h"
+#include "rcc.h"
+#include "gpio.h"
+#include "dac.h"
+
+// Only one, so global to this file
+DAC_Map *dac = (DAC_Map*)(DAC_BASE);
+
+// This numbering follows the registers (1-indexed)
+#define DAC_CHA     1
+#define DAC_CHB     2
+
+// Sets up the DAC peripheral
+void dac_init(void) {
+
+    // First turn on the clock
+    rcc_enable_clk_dac();
+
+    // Then setup ANALOG mode on PA4 and PA5 
+    gpio_set_mode(GPIOA_BASE,  4, CNF_INPUT_ANALOG);
+    gpio_set_mode(GPIOA_BASE,  5, CNF_INPUT_ANALOG);
+
+    // Then do register stuff.
+    // Default does no triggering, and buffered output, so all good.
+    dac->CR |= DAC_CR_EN1;
+    dac->CR |= DAC_CR_EN2;
+
+}
+
+void dac_write(uint8 chan, uint16 val) {
+
+    switch(chan) {
+        case DAC_CHA:
+            dac->DHR12R1 = 0x0FFF & val;
+            break;
+        case DAC_CHB:
+            dac->DHR12R2 = 0x0FFF & val;
+            break;
+        default:    
+            ASSERT(0);  // Shouldn't get here
+    }
+}
diff --git a/libmaple/dac.h b/libmaple/dac.h
new file mode 100644
index 0000000..de1fd3f
--- /dev/null
+++ b/libmaple/dac.h
@@ -0,0 +1,108 @@
+/* *****************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2010 Bryan Newbold.
+ *
+ * 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.
+ * ****************************************************************************/
+
+/* 
+ * See ../notes/dac.txt for more info
+ */
+
+#ifndef _DAC_H_
+#define _DAC_H_
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+#define DAC_BASE  0x40007400
+
+typedef struct {
+   volatile uint32 CR;
+   volatile uint32 SWTRIGR;
+   volatile uint32 DHR12R1;
+   volatile uint32 DHR12L1;
+   volatile uint32 DHR8R1;
+   volatile uint32 DHR12R2;
+   volatile uint32 DHR12L2;
+   volatile uint32 DHR8R2;
+   volatile uint32 DHR12RD;
+   volatile uint32 DHR12LD;
+   volatile uint32 DHR8RD;
+   volatile uint32 DOR1;
+   volatile uint32 DOR2;
+} DAC_Map;
+
+
+// And here are the register bit ranges
+#define DAC_CR_EN1      BIT(0)
+#define DAC_CR_BOFF1    BIT(1)
+#define DAC_CR_TEN1     BIT(2)
+#define DAC_CR_TSEL1    (BIT(3) | BIT(4) | BIT(5))
+#define DAC_CR_WAVE1    (BIT(6) | BIT(7))
+#define DAC_CR_MAMP1    (BIT(8) | BIT(9) | BIT(10) | BIT(11))
+#define DAC_CR_DMAEN1   BIT(12)
+#define DAC_CR_EN2      BIT(16)
+#define DAC_CR_BOFF2    BIT(17)
+#define DAC_CR_TEN2     BIT(18)
+#define DAC_CR_TSEL2    (BIT(19) | BIT(20) | BIT(21))
+#define DAC_CR_WAVE2    (BIT(22) | BIT(23))
+#define DAC_CR_MAMP2    (BIT(24) | BIT(25) | BIT(26) | BIT(27))
+#define DAC_CR_DMAEN2   BIT(28)
+
+#define DAC_SWTRIGR_SWTRIG1     BIT(0)
+#define DAC_SWTRIGR_SWTRIG2     BIT(1)
+
+#define DAC_DHR12R1_DACC1DHR     0x00000FFF
+
+#define DAC_DHR12L1_DACC1DHR     0x0000FFF0 
+
+#define DAC_DHR8R1_DACC1DHR      0x000000FF 
+
+#define DAC_DHR12R2_DACC2DHR     0x00000FFF 
+
+#define DAC_DHR12L2_DACC2DHR     0x0000FFF0
+
+#define DAC_DHR8R2_DACC2DHR      0x000000FF 
+
+#define DAC_DHR12RD_DACC1DHR     0x00000FFF
+#define DAC_DHR12RD_DACC2DHR     0x0FFF0000
+
+#define DAC_DHR12LD_DACC1DHR     0x0000FFF0 
+#define DAC_DHR12LD_DACC2DHR     0xFFF00000
+
+#define DAC_DHR8RD_DACC1DHR      0x000000FF
+#define DAC_DHR8RD_DACC2DHR      0x0000FF00
+
+#define DAC_DOR1                 0x00000FFF 
+
+#define DAC_DOR2                 0x00000FFF 
+
+
+void dac_init(void);
+void dac_write(uint8 chan, uint16 val);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+
+#endif
diff --git a/libmaple/rcc.h b/libmaple/rcc.h
index 8ad70e5..2dca151 100644
--- a/libmaple/rcc.h
+++ b/libmaple/rcc.h
@@ -139,6 +139,7 @@ struct rcc_device {
 #define RCC_APB1ENR_USART3EN   BIT(18)
 #define RCC_APB1ENR_SPI2EN     BIT(14)
 #define RCC_APB1ENR_USB        BIT(23)
+#define RCC_APB1ENR_DACEN      BIT(29)
 
 /* AHB peripheral clock enable bits  */
 #define RCC_AHBENR_DMA1EN      BIT(0)
@@ -174,6 +175,8 @@ struct rcc_device {
 
 #define rcc_enable_clk_adc1()     __set_bits(RCC_APB2ENR, RCC_APB2ENR_ADC1EN)
 
+#define rcc_enable_clk_dac()      __set_bits(RCC_APB1ENR, RCC_APB1ENR_DACEN)
+
 #define rcc_reset_adc1()          { __set_bits(RCC_APB2RSTR, RCC_APB2RSTR_ADC1RST);   \
                                     __clear_bits(RCC_APB2RSTR, RCC_APB2RSTR_ADC1RST); \
                                   }
diff --git a/libmaple/rules.mk b/libmaple/rules.mk
index db9540a..8428277 100644
--- a/libmaple/rules.mk
+++ b/libmaple/rules.mk
@@ -26,6 +26,7 @@ cSRCS_$(d) := systick.c                \
               flash.c                  \
               spi.c                    \
 			  fsmc.c				   \
+			  dac.c					   \
               usb/usb.c                \
               usb/usb_callbacks.c      \
               usb/usb_hardware.c       \
diff --git a/notes/dac.txt b/notes/dac.txt
new file mode 100644
index 0000000..9df0782
--- /dev/null
+++ b/notes/dac.txt
@@ -0,0 +1,32 @@
+
+DAC notes (for maple native and other "high density" STM32 devices)
+-------------------------------------------------------------------------------
+There is an ST application note for the DACs; it provides a lot of context but
+doesn't help setup the peripheral very much.
+
+For the first code iteration we'll just use 12-bit right-aligned single writes, 
+so use DAC_DHR12Rx
+
+Once data is loaded into the digital registers, there are a number of possible
+triggers to start conversion to analog output: external interrupts, software
+control, and timer events. We'll just use software triggering for now.
+
+There is (obviously) DMA support for DAC output.
+
+There are noise output and triangle wave output features with variable
+amplitude.
+
+There are many additional modes to tigger output to both channels at the same
+time.
+
+Buffering will be enabled by default.
+
+TODO
+-------------------------------------------------------------------------------
+- sine wave demo using Timer interrupts
+- wirish implementation
+- documentation
+- higher performance modes?
+- signal quality testing
+- DMA output
+