Hi Experts!
Summary:
Question: Anyone know if the dual 8bit ADC mode is broken on the STM32H743 or what I could be doing wrong?
Details:
I am trying to get 8 bit dual mode ADC working on the STM32H743.
I see one post on here that seems to indicate some inconsistency with the documentation
However what I am seeing is something really wierd...
Just as background - I am able to get the 16 bit dual mode working just fine using the below setup for ADC1 & ADC2 (Channel 3 on ADC1 and Channel 4 on ADC2) - I am using circular mode DMA...
static void MX_ADC1_Init(void)
{
/* USER CODE BEGIN ADC1_Init 0 */
/* USER CODE END ADC1_Init 0 */
ADC_MultiModeTypeDef multimode = {0};
ADC_ChannelConfTypeDef sConfig = {0};
/* USER CODE BEGIN ADC1_Init 1 */
/* USER CODE END ADC1_Init 1 */
/** Common config
*/
hadc1.Instance = ADC1;
hadc1.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV2;
hadc1.Init.Resolution = ADC_RESOLUTION_16B;
hadc1.Init.ScanConvMode = ADC_SCAN_DISABLE;
hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
hadc1.Init.LowPowerAutoWait = DISABLE;
hadc1.Init.ContinuousConvMode = DISABLE;
hadc1.Init.NbrOfConversion = 1;
hadc1.Init.DiscontinuousConvMode = DISABLE;
hadc1.Init.ExternalTrigConv = ADC_EXTERNALTRIG_T2_TRGO;
hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_RISINGFALLING;
hadc1.Init.ConversionDataManagement = ADC_CONVERSIONDATA_DMA_CIRCULAR;
hadc1.Init.Overrun = ADC_OVR_DATA_OVERWRITTEN;
hadc1.Init.LeftBitShift = ADC_LEFTBITSHIFT_NONE;
hadc1.Init.OversamplingMode = DISABLE;
if (HAL_ADC_Init(&hadc1) != HAL_OK)
{
Error_Handler();
}
/** Configure the ADC multi-mode
*/
multimode.Mode = ADC_DUALMODE_REGSIMULT;
multimode.DualModeData = ADC_DUALMODEDATAFORMAT_32_10_BITS;//ADC_DUALMODEDATAFORMAT_8_BITS;//
multimode.TwoSamplingDelay = ADC_TWOSAMPLINGDELAY_1CYCLE;
if (HAL_ADCEx_MultiModeConfigChannel(&hadc1, &multimode) != HAL_OK)
{
Error_Handler();
}
/** Configure Regular Channel
*/
sConfig.Channel = ADC_CHANNEL_3;
sConfig.Rank = ADC_REGULAR_RANK_1;
sConfig.SamplingTime = ADC_SAMPLETIME_1CYCLE_5;
sConfig.SingleDiff = ADC_SINGLE_ENDED;
sConfig.OffsetNumber = ADC_OFFSET_NONE;
sConfig.Offset = 0;
if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN ADC1_Init 2 */
/* USER CODE END ADC1_Init 2 */
}
static void MX_ADC2_Init(void)
{
/* USER CODE BEGIN ADC2_Init 0 */
/* USER CODE END ADC2_Init 0 */
ADC_ChannelConfTypeDef sConfig = {0};
/* USER CODE BEGIN ADC2_Init 1 */
/* USER CODE END ADC2_Init 1 */
/** Common config
*/
hadc2.Instance = ADC2;
hadc2.Init=hadc1.Init;
hadc2.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV2;
hadc2.Init.Resolution = ADC_RESOLUTION_16B;
hadc2.Init.ScanConvMode = ADC_SCAN_DISABLE;
hadc2.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
hadc2.Init.LowPowerAutoWait = DISABLE;
hadc2.Init.ContinuousConvMode = DISABLE;
hadc2.Init.NbrOfConversion = 1;
hadc2.Init.DiscontinuousConvMode = DISABLE;
hadc2.Init.ConversionDataManagement = ADC_CONVERSIONDATA_DMA_CIRCULAR;
hadc2.Init.Overrun = ADC_OVR_DATA_OVERWRITTEN;
hadc2.Init.LeftBitShift = ADC_LEFTBITSHIFT_NONE;
hadc2.Init.OversamplingMode = DISABLE;
hadc2.Init.ExternalTrigConv = ADC_SOFTWARE_START;
if (HAL_ADC_Init(&hadc2) != HAL_OK)
{
Error_Handler();
}
/** Configure Regular Channel
*/
sConfig.Channel = ADC_CHANNEL_4;
sConfig.Rank = ADC_REGULAR_RANK_1;
sConfig.SamplingTime = ADC_SAMPLETIME_1CYCLE_5;
sConfig.SingleDiff = ADC_SINGLE_ENDED;
sConfig.OffsetNumber = ADC_OFFSET_NONE;
sConfig.Offset = 0;
if (HAL_ADC_ConfigChannel(&hadc2, &sConfig) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN ADC2_Init 2 */
/* USER CODE END ADC2_Init 2 */
}
With the above config - I get the ADC Channel 3 data in CDR register bits [0..15] and ADC Channel 4 in CDR [15..32] - as expected.
I can scale it down to 8 bits, but if I can get down to 8 bit resolution it would be ideal -
Per RM0433 if I set DAMDF=0b11 (8 bit mode) I am supposed to get
And then the 1st DMA request would be generated.
However I never get the full word populated I only seem to get the lower 16 bits in CDR and the Slave channel appears to have junk.
There is an ADC errata https://www.st.com/resource/en/errata_sheet/es0392-stm32h742xig-stm32h743xig-stm32h750xb-stm32h753xi-device-errata-stmicroelectronics.pdf
That seems to mention
It seems sort of related but the workaround did not fix anything.
Question: Anyone know if the 8bit ADC mode is broken on the STM32H743 or what I could be doing wrong?
Thanks for any and all help!
