ECG 2 Click Board

The ECG 2 Click Board™ works best with a battery power supply. In cases where the board is powered through an USB cable, a periodical 50Hz noise will occur on the ECG signal. To counter this noise, the user must place their left hand on the ground pin of their development board.

Code set's up the ECG 2 Click Board™, measures ECG and sends data to MikroPlot application.

01: void main() {
02:
03: uint16_t i = 0;
04: char final_string[20];
05: char time_string[20];
06: double time_value = 0.0;
07: UART0_Init(57600);
08: delay_ms(300);
09:
10: GPIO_Digital_Input(&GPIO_PORTH, _GPIO_PINMASK_0); // pin DRDY is input
11: GPIO_Digital_Output(&GPIO_PORTC, _GPIO_PINMASK_4); // pin PWDN is output
12: ECG2_PWDN = 1; // ECG2 is powered up
13: GPIO_Digital_Output(&GPIO_PORTG, _GPIO_PINMASK_0); // pin CS is output
14: ECG2_CS = 1; // deselect ECG2 click
15: GPIO_Digital_Output(&GPIO_PORTE, _GPIO_PINMASK_2); // pin RESET is output
16: ECG2_RESET = 1; // pull RESET bit low for 18 CLK to RESET ECG device
17:
18: // init SPI
19: SPI0_Init_Advanced(500000, _SPI_MASTER, _SPI_8_BIT | _SPI_CLK_IDLE_LOW | _SPI_SECOND_CLK_EDGE_TRANSITION, &_GPIO_MODULE_SPI0_A245);
20: ecg2_hal_init();
21:
22:
23: // issue RESET pulse
24: ECG2_RESET = 0;
25: Delay_us(100);
26: ECG2_RESET = 1;
27:
28: Delay_ms(1000);
29:
30: // device is in RDATAC mode, set it to SDATAC mode to edit registers
31: ecg2_hal_send_command(SDATAC_COMMAND);
32: delay_ms(1000);
33: setup_ecg2();
34:
35: while (1)
36: {
37: while (ECG2_DRDY) {} // Wait for ADS1194 device to prepare output data. Data is ready every 8 milliseconds
38: Delay_us(5);
39: for (i = 0; i < num_bytes_sample; i++)
40: ecg_data_sample[i] = SPI_Read(0); // read ADS1194 output data, one sample
41:
42: time_value += 8.0; // increment time value
43: // calculate input voltage
44: // voltage LA RA
45: channel1_voltage = calculate_ecg_channel( ecg_data_sample, 3, Vref, channel_gain, channel1_voltage_offset );
46: // voltage LL RA - channel 2 is usually used for simple ECG
47: channel2_voltage = calculate_ecg_channel( ecg_data_sample, 5, Vref, channel_gain, channel2_voltage_offset );
48: sprintf(final_string, "%.2f", channel2_voltage); // convert values to string and send to MikroPlot
49: strcat(final_string, ",");
50: sprintf(time_string, "%.2f", time_value);
51: strcat(final_string, time_string);
52: Uart_Write_Text(final_string);
53: Uart_Write_Text("rn");
54:
55: // voltage LL LA
56: channel3_voltage = calculate_ecg_channel( ecg_data_sample, 7, vref, channel_gain, channel3_voltage_offset );
57: // voltage from temperature sensor
58: channel4_voltage = calculate_ecg_channel( ecg_data_sample, 9, vref, channel_gain, channel4_voltage_offset );
59: }
60: }