ADC1 and TIM1 Synchronized 250 Hz Sampling

What I checked first

Across the ECG variants, the common structure uses the TIM1 update interrupt as the sample clock and reads ADC1 once. The 250 Hz version transmits sample_index and timestamp_us, applies a five-sample moving average, and then filters the sample.

Source view

• The 12-bit ADC value is converted to voltage with 3.3/4095.
• ADC polling and UART transfer time must be checked against the sampling period.
• The source shows the timing structure, but no saved jitter measurement is available.

Code path

#define ECG_FS_HZ 250U
sample_index++;
HAL_ADC_Start(&hadc1);
ADCValue = HAL_ADC_GetValue(&hadc1);
Smooth_ECG = total / numReadings;
timestamp_us = sample_index * 1000000ULL / ECG_FS_HZ;

Key terms

1. TIM1 interrupt
2. ADC1
3. 250 Hz
4. sample index

Review sequence

1. TIM1 interrupt
2. ADC1 → 250 Hz
3. sample index