ADC3 Oversampling Ratio incorrectly set

[heinwessels]

The Bug In the function LL_ADC_ConfigOverSamplingRatioShift (and corresponding LL_ADC_GetOverSamplingRatio) the CFGR2->OVSR does not handle all cases correctly.

More detail For example, for STM32H723's the CFGR2->OVSR field is different for ADC1+2 and ADC3.

For ADC1 and ADC2:

Bits 25:16 OSVR[9:0]: Oversampling ratio This bitfield is set and cleared by software to define the oversampling ratio. 0: 1x (no oversampling) 1: 2x 2: 3x ... 1023: 1024x

For ADC3:

Bits 4:2 OVSR[2:0]: Oversampling ratio This bitfield is set and cleared by software to define the oversampling ratio. 000: 2x 001: 4x 010: 8x 011: 16x 100: 32x 101: 64x 110: 128x 111: 256x

Currently the LL dirver does not handle this special case.

Proposed Solution Follow how the other functions handled this special case. For example:

__STATIC_INLINE void LL_ADC_ConfigOverSamplingRatioShift(ADC_TypeDef *ADCx, uint32_t Ratio, uint32_t Shift)
{
  MODIFY_REG(ADCx->CFGR2, ADC_CFGR2_OVSS, Shift);
#if defined(ADC_VER_V5_V90)
  if (ADCx == ADC3) {
      MODIFY_REG(adc->CFGR2, ADC3_CFGR2_OVSR, (Ratio - 1UL) << ADC3_CFGR2_OVSR_Pos);
  } else {
#endif
      MODIFY_REG(adc->CFGR2, ADC_CFGR2_OVSR, (Ratio - 1UL) << ADC_CFGR2_OVSR_Pos);
if defined(ADC_VER_V5_V90)
  }
#endif
}

Edit: It seems all H7 devices has the ratio set from 0->1023 for ADC1 and 2.

[FRASTM]

Could this issue be a duplicate of the https://github.com/STMicroelectronics/STM32CubeH7/issues/170?

[heinwessels]

Could this issue be a duplicate of the #170?

@FRASTM definitely not, since I raised both these issues myself. They are probably related, but not duplicates. They point to different functions:

#170: LL_ADC_SetResolution(adc, LL_ADC_RESOLUTION_12B); #177: LL_ADC_ConfigOverSamplingRatioShift(...)

[RKOUSTM]

Hi @heinwessels,

Thank you for this contribution. An internal tracker has been logged and a fix will be implemented and made available in the frame of a future release.

Thank you once more for your contribution.

With regards

[RKOUSTM]

ST Internal Reference: 116019