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-rw-r--r--examples/test-dac.cpp50
-rw-r--r--libmaple/dac.c16
-rw-r--r--libmaple/dac.h2
-rw-r--r--libmaple/rcc.c2
-rw-r--r--notes/dac.txt24
5 files changed, 50 insertions, 44 deletions
diff --git a/examples/test-dac.cpp b/examples/test-dac.cpp
index 65496f4..3a699e2 100644
--- a/examples/test-dac.cpp
+++ b/examples/test-dac.cpp
@@ -5,49 +5,41 @@
#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);
+ pinMode(BOARD_LED_PIN, OUTPUT);
+ digitalWrite(BOARD_LED_PIN,1);
- Serial1.begin(9600);
- Serial1.println("Hello World!");
+ Serial1.begin(9600);
+ Serial1.println("**** Beginning DAC test");
- Serial1.print("Init... ");
- dac_init();
- Serial1.println("Done.");
+ Serial1.print("Init... ");
+ dac_init();
+ Serial1.println("Done.");
}
void loop() {
- digitalWrite(LED_PIN, toggle);
- toggle ^= 1;
- delay(100);
-
- count += 100;
+ toggleLED();
+ delay(100);
- if(count > 4095) {
- count = 0;
- }
+ count += 100;
+ if(count > 4095) {
+ count = 0;
+ }
- dac_write(1, 2048);
- dac_write(2, count);
+ dac_write(1, 2048);
+ dac_write(2, count);
}
int main(void) {
- init();
- setup();
+ init();
+ setup();
- while (1) {
- loop();
- }
- return 0;
+ while (1) {
+ loop();
+ }
+ return 0;
}
diff --git a/libmaple/dac.c b/libmaple/dac.c
index 7f6101d..63a96ac 100644
--- a/libmaple/dac.c
+++ b/libmaple/dac.c
@@ -31,12 +31,11 @@
* @brief DAC peripheral routines.
*/
-/* 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
+#define DAC_CH1 1
+#define DAC_CH2 2
+
+DAC_Map *dac = (DAC_Map*)(DAC_BASE);
/* Sets up the DAC peripheral */
void dac_init(void) {
@@ -49,16 +48,15 @@ void dac_init(void) {
/* Then do register stuff. Default does no triggering, and
* buffered output, so all good. */
- dac->CR |= DAC_CR_EN1;
- dac->CR |= DAC_CR_EN2;
+ dac->CR = DAC_CR_EN1 | DAC_CR_EN2;
}
void dac_write(uint8 chan, uint16 val) {
switch(chan) {
- case DAC_CHA:
+ case DAC_CH1:
dac->DHR12R1 = 0x0FFF & val;
break;
- case DAC_CHB:
+ case DAC_CH2:
dac->DHR12R2 = 0x0FFF & val;
break;
default:
diff --git a/libmaple/dac.h b/libmaple/dac.h
index 9c84f2e..340a49a 100644
--- a/libmaple/dac.h
+++ b/libmaple/dac.h
@@ -55,6 +55,8 @@ typedef struct {
volatile uint32 DOR2;
} DAC_Map;
+/* There's only one DAC, so expose it. */
+extern DAC_Map *dac;
// And here are the register bit ranges
#define DAC_CR_EN1 BIT(0)
diff --git a/libmaple/rcc.c b/libmaple/rcc.c
index 313eaf7..6905c22 100644
--- a/libmaple/rcc.c
+++ b/libmaple/rcc.c
@@ -70,7 +70,7 @@ static const struct rcc_dev_info rcc_dev_table[] = {
[RCC_SPI1] = { .clk_domain = APB2, .line_num = 12 },
[RCC_SPI2] = { .clk_domain = APB1, .line_num = 14 },
[RCC_FSMC] = { .clk_domain = AHB, .line_num = 8 }, // High-density only
- [RCC_DAC] = { .clk_domain = APB1, .line_num = 9 }, // High-density only
+ [RCC_DAC] = { .clk_domain = APB1, .line_num = 29 }, // High-density only
[RCC_DMA1] = { .clk_domain = AHB, .line_num = 0 },
[RCC_DMA2] = { .clk_domain = AHB, .line_num = 1 }, // High-density only
};
diff --git a/notes/dac.txt b/notes/dac.txt
index 9df0782..d027402 100644
--- a/notes/dac.txt
+++ b/notes/dac.txt
@@ -13,11 +13,25 @@ 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.
+There are noise (via LFSR) output and triangle wave output features
+with variable amplitude.
+
+There are eleven modes to trigger output to both channels at the same
+time, as follows:
+
+ - Independent trigger:
+ (1) No wave generation
+ (2) Same LFSR
+ (3) Different LFSR
+ (4) Same triangle
+ (5) Different triangle
+ - (6) Simultaneous software start
+ - Simultaneous trigger:
+ (7) Without wave generation
+ (8) Same LFSR
+ (9) Different LFSR
+ (10) Same triangle
+ (11) Different triangle
Buffering will be enabled by default.