diff options
| -rw-r--r-- | stmhal/adc.c | 35 |
1 files changed, 31 insertions, 4 deletions
diff --git a/stmhal/adc.c b/stmhal/adc.c index 867edc6486..e88119567a 100644 --- a/stmhal/adc.c +++ b/stmhal/adc.c @@ -225,22 +225,49 @@ STATIC mp_obj_t adc_read_timed(mp_obj_t self_in, mp_obj_t buf_in, mp_obj_t freq_ // Start timer HAL_TIM_Base_Start(&TIM6_Handle); - // This uses the timer in polling mode to do the sampling - // We could use DMA, but then we can't convert the values correctly for the buffer + // configure the ADC channel adc_config_channel(self); + + // This uses the timer in polling mode to do the sampling + // TODO use DMA + uint nelems = bufinfo.len / typesize; for (uint index = 0; index < nelems; index++) { - // Wait for the timer to trigger + // Wait for the timer to trigger so we sample at the correct frequency while (__HAL_TIM_GET_FLAG(&TIM6_Handle, TIM_FLAG_UPDATE) == RESET) { } __HAL_TIM_CLEAR_FLAG(&TIM6_Handle, TIM_FLAG_UPDATE); - uint value = adc_read_channel(&self->handle); + + if (index == 0) { + // for the first sample we need to turn the ADC on + HAL_ADC_Start(&self->handle); + } else { + // for subsequent samples we can just set the "start sample" bit + ADCx->CR2 |= (uint32_t)ADC_CR2_SWSTART; + } + + // wait for sample to complete + uint32_t tickstart = HAL_GetTick(); + while ((ADCx->SR & ADC_FLAG_EOC) != ADC_FLAG_EOC) { + #define READ_TIMED_TIMEOUT (10) // in ms + if (((HAL_GetTick() - tickstart ) > READ_TIMED_TIMEOUT)) { + break; // timeout + } + } + + // read value + uint value = ADCx->DR; + + // store value in buffer if (typesize == 1) { value >>= 4; } mp_binary_set_val_array_from_int(bufinfo.typecode, bufinfo.buf, index, value); } + // turn the ADC off + HAL_ADC_Stop(&self->handle); + // Stop timer HAL_TIM_Base_Stop(&TIM6_Handle); |