stm32/adc: Increase sample time for internal sensors on L4 MCUs.
They need time (around 4us for VREFINT) to obtain accurate results.
Fixes issue
@@ -304,7 +304,13 @@ STATIC void adc_config_channel(ADC_HandleTypeDef *adc_handle, uint32_t channel)
sConfig.OffsetRightShift = DISABLE;
sConfig.OffsetSignedSaturation = DISABLE;
#elif defined(STM32L4)
+ if (channel == ADC_CHANNEL_VREFINT
+ || channel == ADC_CHANNEL_TEMPSENSOR
+ || channel == ADC_CHANNEL_VBAT) {
+ sConfig.SamplingTime = ADC_SAMPLETIME_247CYCLES_5;
+ } else {
sConfig.SamplingTime = ADC_SAMPLETIME_12CYCLES_5;
+ }
sConfig.SingleDiff = ADC_SINGLE_ENDED;
sConfig.OffsetNumber = ADC_OFFSET_NONE;
sConfig.Offset = 0;
