Application examples

AN4207

24/28

Doc ID 023945 Rev 1

4.4

ElectroCardioGram (ECG) acquisition

This application shows how to use the 16-bit Sigma-Delta Analog-to-Digital converter to

acquire a human ECG using two ECG electrodes TS1 and TS2 installed on the

STM32373C-EVAL evaluation board.

The application source code is available in the

Project\STM32373C-EVAL\src\applications.c

file in the STM32373C-EVAL demonstration firmware package stm32373c-eval_fw

Two ECG electrodes TS1 and TS2 are connected to SDADC1 channel 0 (PE12) through an

ECG amplifier/filter. The SDADC is configured in Single-Ended Zero Reference mode and

conversion is triggered by the TIM3 timer at a sampling rate of 480 Hz.

The ECG acquisition application uses a ping-pong buffer: one buffer is actively being filtered

(using a bandpass filter) and then displayed on the LCD while the second buffer is filled with

the new ECG samples.

Note:

ECG samples are filtered using the ARM DSP library

Figure 14 below shows the block diagram of the electrocardiogram acquisition application.

Figure 14.

Block diagram of the electrocardiogram (ECG) acquisition application

MSv31141V1

1st buffer

2nd buffer

16-bit

ΣΔ

SDADC

TIM13

480/sec

ECG

AOP

SRAM

SPI

Cortex M4

CPU wth FPU/

MPU

72 MHz

STM32F37x

DMA