Posted on February 08, 2017 at 19:25Hello,
I am using the the HAL library for calibrating the DAC on STM32L4.
I read the documentation for DAC on page 286 (DOCID027704 Rev 4) in HAL L4 user manual. I am still confused about how to correctly use the HAL DAC calibration APIs.
My question is how does the
HAL_DACEx_SelfCalibrate() API work? Does it automatically apply the trimming offset?
or do I also need to use the APIs below?
HAL_DACEx_GetTrimOffset()
HAL_DACEx_SetUserTrimming()
If yes should I be manually adding the TrimOffset before making a call to
HAL_DAC_SetValue, s
omething like below?
trim_offset = HAL_DACEx_GetTrimOffset(&hdac1, DAC_CHANNEL_2)
HAL_DAC_SetValue(&hdac1, DAC_CHANNEL_2, DAC_ALIGN_8B_R, input_data + trim_offset )?
Just for reference I have posted my current code below.
Below is my current calibration function:
void DAC_SelfCalibrate(void)
{
DAC_ChannelConfTypeDef sConfig;
sConfig.DAC_SampleAndHold = DAC_SAMPLEANDHOLD_DISABLE;
sConfig.DAC_Trigger = DAC_TRIGGER_NONE;
sConfig.DAC_OutputBuffer = DAC_OUTPUTBUFFER_ENABLE;
sConfig.DAC_ConnectOnChipPeripheral = DAC_CHIPCONNECT_DISABLE;
sConfig.DAC_UserTrimming = DAC_TRIMMING_USER;
//Calibrate DAC channel 1
if (HAL_DACEx_SelfCalibrate(&hdac1, &sConfig, DAC_CHANNEL_1) != HAL_OK)
{
Error_Handler();
}
//Calibrate DAC channel 2
sConfig.DAC_ConnectOnChipPeripheral = DAC_CHIPCONNECT_DISABLE;
if (HAL_DAC_ConfigChannel(&hdac1, &sConfig, DAC_CHANNEL_2) != HAL_OK)
{
Error_Handler();
}
}
and here is my code to set the DAC
int set_dac_val(uint8_t input_index, uint8_t input_data)
{
//set dac channel 1
if(input_index==0) {
HAL_DAC_SetValue(&hdac1, DAC_CHANNEL_1, DAC_ALIGN_8B_R, input_data);
//set dac channel 2
}
else if(input_index==1)
{
HAL_DAC_SetValue(&hdac1, DAC_CHANNEL_2, DAC_ALIGN_8B_R, input_data);
}
return 0;
}
Below is my sequence of calls for initialization.
MX_DAC1_Init();
DAC_SelfCalibrate();
HAL_DAC_Start(&hdac1, DAC_CHANNEL_1);
HAL_DAC_Start(&hdac1, DAC_CHANNEL_2);
I have a similar question about HAL based ADC calibration and usage of calibration factor. I will post that under a separate thread.
Thanks!
#hal #dac #calibration
