Hello,
I am generating a waveform by using the DAC, channel 1 in circular mode. Timer 7 is configured as trigger out even in DAC out1 settings.
When I generate values manually (without the DMA) everything works as expected but if I use the DMA the output is kind of random waveform.
What could be the problem?
Thanks,
The code is:
uint16_t sine_wave_array[32] = {0x80,0x98,0xb0,0xc6,0xda,0xea,0xf5,0xfd,
0xff,0xfd,0xf5,0xea,0xda,0xc6,0xb0,0x98,
0x80,0x67,0x4f,0x39,0x25,0x15,0xa,0x2,
0x0,0x2,0xa,0x15,0x25,0x39,0x4f,0x67};
HAL_TIM_Base_Start(&htim7);
__HAL_TIM_ENABLE(&htim7);
HAL_DAC_Start(&hdac,DAC_CHANNEL_1);
HAL_DAC_Start_DMA(&hdac, DAC_CHANNEL_1, (uint32_t*)sine_wave_array, 32, DAC_ALIGN_12B_R);
while(1)
{}
The working code is (in this case I use timer6 to generate a delay):
while(1)
{
tmp = (uint32_t)hdac.Instance + DAC_DHR12R1_ALIGNMENT(DAC_ALIGN_12B_R);
*(__IO uint32_t *) tmp = sine_wave_array[i++];
if(i>31){i=0;}
TIM6->CNT= 0; while(TIM6->CNT < 100);
}
DAC init is:
hdac.Instance = DAC;
if (HAL_DAC_Init(&hdac) != HAL_OK)
{
Error_Handler();
}
/** DAC channel OUT1 config
*/
sConfig.DAC_Trigger = DAC_TRIGGER_T7_TRGO;
sConfig.DAC_OutputBuffer = DAC_OUTPUTBUFFER_ENABLE;
if (HAL_DAC_ConfigChannel(&hdac, &sConfig, DAC_CHANNEL_1) != HAL_OK)
{
Error_Handler();
}
Timer 7 init is:
static void MX_TIM7_Init(void)
{
/* USER CODE BEGIN TIM7_Init 0 */
/* USER CODE END TIM7_Init 0 */
TIM_MasterConfigTypeDef sMasterConfig = {0};
/* USER CODE BEGIN TIM7_Init 1 */
/* USER CODE END TIM7_Init 1 */
htim7.Instance = TIM7;
htim7.Init.Prescaler = 0;
htim7.Init.CounterMode = TIM_COUNTERMODE_UP;
htim7.Init.Period = 32768;
htim7.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
if (HAL_TIM_Base_Init(&htim7) != HAL_OK)
{
Error_Handler();
}
sMasterConfig.MasterOutputTrigger = TIM_TRGO_UPDATE;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim7, &sMasterConfig) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN TIM7_Init 2 */
/* USER CODE END TIM7_Init 2 */
}
