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stm32/adc: Add workaround for ADC errata with G4 MCUs.

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For STM32G4, there is a errata on ADC that may get wrong ADC result.
According to the errata sheet, this can be avoid by performing two
consecutive ADC conversions and keep second result.

Signed-off-by: Yuuki NAGAO <wf.yn386@gmail.com>
This commit is contained in:
Yuuki NAGAO 2023-07-08 11:14:00 +09:00 committed by Damien George
parent 0a31b9bf78
commit cb38f77918
2 changed files with 27 additions and 9 deletions
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15
ports/stm32/adc.c
View file

@ -458,9 +458,18 @@ STATIC void adc_config_channel(ADC_HandleTypeDef *adc_handle, uint32_t channel)
} }
STATIC uint32_t adc_read_channel(ADC_HandleTypeDef *adcHandle) { STATIC uint32_t adc_read_channel(ADC_HandleTypeDef *adcHandle) {
HAL_ADC_Start(adcHandle); uint32_t value;
adc_wait_for_eoc_or_timeout(adcHandle, EOC_TIMEOUT); #if defined(STM32G4)
uint32_t value = adcHandle->Instance->DR; // For STM32G4 there is errata 2.7.7, "Wrong ADC result if conversion done late after
// calibration or previous conversion". According to the errata, this can be avoided
// by performing two consecutive ADC conversions and keeping the second result.
for (uint8_t i = 0; i < 2; i++)
#endif
{
HAL_ADC_Start(adcHandle);
adc_wait_for_eoc_or_timeout(adcHandle, EOC_TIMEOUT);
value = adcHandle->Instance->DR;
}
HAL_ADC_Stop(adcHandle); HAL_ADC_Stop(adcHandle);
return value; return value;
} }

21
ports/stm32/machine_adc.c
View file

@ -371,13 +371,22 @@ STATIC void adc_config_channel(ADC_TypeDef *adc, uint32_t channel, uint32_t samp
} }
STATIC uint32_t adc_read_channel(ADC_TypeDef *adc) { STATIC uint32_t adc_read_channel(ADC_TypeDef *adc) {
#if ADC_V2 uint32_t value;
adc->CR |= ADC_CR_ADSTART; #if defined(STM32G4)
#else // For STM32G4 there is errata 2.7.7, "Wrong ADC result if conversion done late after
adc->CR2 |= ADC_CR2_SWSTART; // calibration or previous conversion". According to the errata, this can be avoided
// by performing two consecutive ADC conversions and keeping the second result.
for (uint8_t i = 0; i < 2; i++)
#endif #endif
adc_wait_eoc(adc, ADC_EOC_TIMEOUT_MS); {
uint32_t value = adc->DR; #if ADC_V2
adc->CR |= ADC_CR_ADSTART;
#else
adc->CR2 |= ADC_CR2_SWSTART;
#endif
adc_wait_eoc(adc, ADC_EOC_TIMEOUT_MS);
value = adc->DR;
}
return value; return value;
} }