Posted on December 15, 2011 at 10:31
Hi. I'm trying to get an output from the internal DAC without using DMA, but the examples all use DMA.
My code looks like this:
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM6, ENABLE);
/* Time base configuration */
TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
TIM_TimeBaseStructure.TIM_Period = 0xFF;
TIM_TimeBaseStructure.TIM_Prescaler = 0;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM6, &TIM_TimeBaseStructure);
/* TIM6 TRGO selection */
TIM_SelectOutputTrigger(TIM6, TIM_TRGOSource_Update);
/* TIM6 enable counter */
TIM_Cmd(TIM6, ENABLE);
/* DAC Config */
DAC_InitTypeDef DAC_InitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);
DAC_InitStructure.DAC_Trigger = DAC_Trigger_T6_TRGO;
DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
DAC_Init(DAC_Channel_1, &DAC_InitStructure);
DAC_Cmd(DAC_Channel_1, ENABLE);
while
(1){
DAC_SetChannel1Data(DAC_Align_12b_R, 4095);
}
As you can see, I'm using TIM6 as a trigger update. The channel data can be any number from 0 to 4095 (4095 here, but I've tried several numbers in a loop). I've tried changing the GPIO_Mode to OUT instead of AN also. I measure in PA4 with a probe, but nothing comes out. The TIM6 though is working fine, I've tried changing a pin testing for the TIM_FLAG_Update and it's firing at the correct rate. I don't thing I've missed any clock config. Any idea?
#stm32f4 #dac
