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bugra
bugra
Associate
April 21, 2014
Question

independent DAC Channel triggers on STMF3XX

  • April 21, 2014
  • 2 replies
  • 977 views
Posted on April 21, 2014 at 07:55

Hi,

I am using STM32F303 to generate 2 sine-waves  on DAC_Channel1 and DAC_Channel2.

I use one lookup table to generate the sine-wave. And I succeded to generate sine-waves on both channels, but the generated signals have the same frequency.

Since I want to have 2 different sine-waves with 2 different frequencies, I want to trigger each DMA channels independently. (ie, 

DAC_Trigger_T6_TRGO for 

DAC_Channel1 and 

DAC_Trigger_T7_TRGO for DAC_Channel2). According to the reference manual, it seems possible. But when I make such configuration DAC stops working I think; because no signals are generated on both channels.

Does it possible to trigger DAC channels independently?

#stm32-dac_trigger
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2 replies

Tesla DeLorean
Tesla DeLorean
Guru
April 21, 2014
Posted on April 21, 2014 at 17:08

Does it possible to trigger DAC channels independently?

 

Yes, I believe it should be
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bugra
bugraAuthor
Associate
April 27, 2014
Posted on April 27, 2014 at 09:04

Thank you Clive.

After you confirmed that it is possible, I inspected my code line-by line and found the problem: 


 /* DAC CONFIG */

/* DAC Periph clock enable */

RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);


/* DAC Channel1 Configuration ******************/

DAC_DeInit(); 

DAC_InitStructure.DAC_Trigger = DAC_Trigger_T6_TRGO;

DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;

DAC_InitStructure.DAC_LFSRUnmask_TriangleAmplitude = DAC_LFSRUnmask_Bits11_0; 
//This line determines the amplitude of SineWave

DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;

/* DAC Channel1 Init */

DAC_Init(DAC_Channel_1, &DAC_InitStructure);


/* Enable DAC Channel1 */

DAC_Cmd(DAC_Channel_1, ENABLE);


/* Enable DMA for DAC Channel1 */

DAC_DMACmd(DAC_Channel_1, ENABLE);


/* DAC Channel2 Configuration ***********************************************************************/

//DAC_DeInit(); // This line SHOULD NOT be executed again, otherwise previous definitions made for configuring DAC_CH1 will be deleted. 

DAC_InitStructure.DAC_Trigger = DAC_Trigger_T7_TRGO;

DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
//DAC_WaveGeneration_Triangle;

DAC_InitStructure.DAC_LFSRUnmask_TriangleAmplitude = DAC_LFSRUnmask_Bits11_0; 
//This line determines the amplitude of SineWave

DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;

/* DAC Channel2 Init */

DAC_Init(DAC_Channel_2, &DAC_InitStructure);


/* Enable DAC Channel2 */

DAC_Cmd(DAC_Channel_2, ENABLE);


/* Enable DMA for DAC Channel2 */

DAC_DMACmd(DAC_Channel_2, ENABLE);

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