STM32 F446RE simple DAC output; what am I missing? - arm

Question

Trying to get some simple DAC output before
moving forward. Have a multimeter on the output A2
but this seems to never change from about 1V6 for whatever value
I put into the DAC2 output function.
#include "stm32f4xx.h"
#include "stm32f4xx_dac.h"
void io_config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* DMA1 & DMA2 clock and GPIOA & GPIOC clock enable */
RCC_AHB1PeriphClockCmd( /*RCC_AHB1Periph_DMA1 | RCC_AHB1Periph_DMA2 |*/
RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOC | RCC_AHB1Periph_GPIOB, ENABLE);
/* DAC Periph clock, TIM2 clock enable */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC | RCC_APB1Periph_TIM2, ENABLE);
/* ADC1 Periph Clock enable */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStructure);
}
DAC_InitTypeDef dac_init_s;
int main(void)
{
unsigned int i, adcr;
i = adcr = 0;
io_config ();
DAC_StructInit(&dac_init_s);
//dac_init_s.DAC_OutputBuffer = DAC_OutputBuffer_Disable;
DAC_Init(DAC_Channel_2, &dac_init_s);
while(1) {
DAC_SetChannel2Data(DAC_Align_12b_R,500);
}
}

Answer 1

I do not use HAL for such a simple peripheral
Enable clock, configure GPIO pin
for channel 1
DAC -> CR |= DAC_CR_EN1;
DAC -> DHR12R1 = 454 /* your value */
for channel 2
DAC -> CR |= DAC_CR_EN2;
DAC -> DHR12R2 = 454 /* your value */
For waveform generation (using TIM6 and DAC Channel 1)
TIM6 -> DIER &= ~(TIM_DIER_UDE);
TIM6 -> DIER |= TIM_DIER_UDE;
TIM6 -> PSC = /* PSC value */
TIM6 -> ARR = /* PSC value */
TIM6 -> CR2 |= TIM_CR2_MMS_1;
DAC -> CR &= ~(DAC_CR_MAMP1 | DAC_CR_WAVE1);
DAC -> CR = DAC_CR_DMAEN1 | DAC_SR_DMAUDR1 | DAC_CR_TEN1 | DAC_CR_BOFF1;
DAC -> CR |= DAC_CR_EN1;
DMA1_Stream5 -> NDTR = /* Number of samples */
DMA1_Stream5 -> PAR = (uint32_t)&(DAC -> DHR12R1);
DMA1_Stream5 -> M0AR = (uint32_t)(/* address of the waveform data */);
DMA1_Stream5 -> CR = (DMA_SxCR_TEIE | DMA_SxCR_CHSEL | DMA_SxCR_CIRC | DMA_SxCR_DIR_0 | DMA_SxCR_EN | DMA_SxCR_PSIZE_0 | DMA_SxCR_MSIZE_0 | DMA_SxCR_MINC | DMA_SxCR_PL_0);
TIM6 -> CR1 |= TIM_CR1_CEN;

Answer 2

OK this WORKS! STM32F446RE NUCLEO DAC OUTPUT simple example
not tied to timers and/or DMA etc. SOLVED !!!
http://imgur.com/a/wuq4a
varsågod!
#include "stm32f4xx.h"
#include "stm32f4xx_dac.h"
void io_config2 (void) {
// Enable clocks for port A and DAC
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_4;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* DAC channel 2 Configuration */
DAC_InitTypeDef DAC_InitStructure2;
DAC_InitStructure2.DAC_Trigger = DAC_Trigger_None;
DAC_InitStructure2.DAC_WaveGeneration = DAC_WaveGeneration_None;
DAC_InitStructure2.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
DAC_Init(DAC_Channel_2, &DAC_InitStructure2);
/* DAC channel 1 Configuration */
DAC_InitTypeDef DAC_InitStructure1;
DAC_InitStructure1.DAC_Trigger = DAC_Trigger_None;
DAC_InitStructure1.DAC_WaveGeneration = DAC_WaveGeneration_None;
DAC_InitStructure1.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
DAC_Init(DAC_Channel_1, &DAC_InitStructure1);
/* Enable DAC Channel 1 and 2 */
DAC_Cmd(DAC_Channel_2, ENABLE);
DAC_Cmd(DAC_Channel_1, ENABLE);
}
DAC_InitTypeDef dac_init_s;
int main(void)
{
unsigned int i, adcr, j, k;
i = adcr = j = k = 0;
io_config2 ();
//DAC_Cmd( DAC_Channel_2, ENABLE);
DAC_Cmd( DAC_Channel_1, ENABLE);
while(1) {
#define OVAL 4095
//DAC_Cmd( DAC_Channel_2, DISABLE);
//DAC_SetChannel2Data(DAC_Align_12b_R, OVAL );
DAC_SetChannel1Data(DAC_Align_12b_R, OVAL ); /* 1000/4096 * 3V3 == 0V8 */
//if ( OVAL != DAC_GetDataOutputValue (DAC_Channel_2)) {
j = DAC_GetDataOutputValue (DAC_Channel_1);
k = DAC_GetDataOutputValue (DAC_Channel_2);
//}
}
}