The code:-

/ ECG ADS1291 Test program. ADS1291 is a single channel ECG chip with a 24 bit Sigma-Delta ADC

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1. include "mbed.h"
2. include <string.h>
3. include <stdio.h>

1. define PIN_MOSI PTA16
2. define PIN_MISO PTA17
3. define PIN_SCLK PTD1 #define PIN_TSC_INTR PTC9

Serial pc(USBTX,USBRX); InterruptIn DRDY_BAR1(PTC8); DigitalIn DRDY_BAR(PTC8); InterruptIn DRDY_BAR(PTD5); DigitalOut CHIPSEL_BAR(PTD0); DigitalOut ADS_START(PTC16); DigitalOut RESET_BAR(PTC17); DigitalOut togg(PTD0);

int freq = 10000; int bits = 8 ; int mode = 1 ; int loop = 1000000 ; unsigned char chk2= 0; unsigned int value = 0; float value = 0; unsigned int value1 = 0; unsigned int value2 = 0; unsigned int value3 = 0; unsigned int value4 = 0; unsigned int value5 = 0; unsigned int value6 = 0; unsigned int data1 = 0; unsigned int count = 0; unsigned int concatenate_value = 0; int concatenate_value = 0; uint32_t adc_buff[2500]; float adc_buff[2500]; SPI commands int CMD_WAKEUP = 0x02; int CMD_STANDBY = 0x04; int CMD_RESET = 0x06; int CMD_START = 0x08; int CMD_STOP = 0x0A; int CMD_OFFSET_CAL = 0x1A; int CMD_RDATAC = 0x10; int CMD_SDATAC = 0x11; int CMD_RDATA = 0x12; Note the following commands are 3 bits and have the following structure CMD_REGr_rrrr; where r_rrrr is the register address given below int CMD_WREG = 0x02; int CMD_RREG = 0x01;

SPI registers addresses, 5 bits width int REG_ID = 0x00; int REG_CONFIG1 = 0x01; int REG_CONFIG2 = 0x02; int REG_LOFF = 0x03; int REG_CH1SET = 0x04; int REG_CH2SET = 0x05; int REG_RLD_SENS = 0x06; int REG_LOFF_SENS = 0x07; int REG_LOFF_STAT = 0x08; int REG_MISC1 = 0x09; int REG_MISC2 = 0x0A; int REG_GIPO = 0x0B;

SPI mySpi(PIN_MOSI, PIN_MISO, PIN_SCLK) ; /* SPI is the spi function written in mbed and mySpi is the instance name*/

typedef void (*func_ptr)(void) ; /*creates typedef to function pointer, does not take any arguement and returns void*/

void doHelp(void) ; void doStatus(void) ; void doFreq(void) ; void doMode(void) ; void doBit(void) ; void doWrite(void) ; void doWrite2(void) ; void doRead(void) ; void doLoop(void) ; void setup(void); void testsetup(void); void ecgsetup(void); void regWrite(int,int); void cmdWrite(int); void regRead(int); void lpf_coef(void); float lpf( float coeff[5], float); void drdy_int(void);

typedef struct _cmd_func { char *name ; func_ptr func ; } cmd_func_type ;

cmd_func_type cmd_list[] = { /*"cmd_func_type cmd_list[]" is same as "struct cmd_list[]"*/ {"help", doHelp}, {"status", doStatus}, {"freq", doFreq}, {"mode", doMode}, {"bit", doBit}, {"write", doWrite}, {"read", doRead}, {"loop", doLoop}, { 0, 0 } } ;

func_ptr getFunc(char *cmd) /*here "func_ptr is same as void*/ { int i = 0 ; while(cmd_list[i].name != 0) { if (strcmp(cmd, cmd_list[i].name) == 0) { return(cmd_list[i].func) ; ; } i++ ; } return(0) ; }

void doHello() { printf("=== spi test program ===\n\r") ; printf("please set your terminal program\n\r") ; printf("local echo on\n\r") ; printf("\n\r") ; }

int main() {

count = 0; unsigned char chk = 1; pc.baud(115200); mySpi.frequency(freq) ; mySpi.format(bits, mode) ; DRDY_BAR1.fall(&doWrite2);

DRDY_BAR1.disable_irq(); DRDY_BAR1.mode(PullUp);

Initialize ADS1291 setup() ;

Put device back in RDATAC mode cmdWrite(CMD_RDATAC) ; printf("The device is in RDATAC mode\n"); Activate conversion, At this point DRDY should toggle ADS_START = 1; int i; printf( "ADC noise data is is= \n"); for(i=0;i<100;i++) { while(DRDY_BAR); doWrite() ; printf( "ADC status is= %X %X %X\n", value1,value2,value3); concatenate_value = ((value4<< 16)|(value5 <<8) |(value6)); printf( "%X\n", concatenate_value); }

testsetup(); wait(0.2); cmdWrite(CMD_RDATAC) ; printf("The device is in RDATAC mode\n"); printf("Test data is\n"); ADS_START = 1; while(1) int j; for(j=0;j<1000;j++) { while(DRDY_BAR); doWrite() ; concatenate_value = ((value4<< 16)|(value5 <<8) |(value6)); value = concatenate_value * 0.000000144243249; printf("%f\n",value); }

ecgsetup(); printf("\n Reading"); DRDY_BAR1.enable_irq(); cmdWrite(CMD_RDATAC) ; printf("The device is in RDATAC mode\n"); ADS_START = 1; chk = 1;

/*while(1) { while(DRDY_BAR); doWrite() ; concatenate_value = ((value4<< 16)|(value5 <<8) |(value6)); value = concatenate_value * 0.0000001442432403564; printf( "%X\n", concatenate_value); printf("%f\n", value); wait(0.5); }*/

DRDY_BAR1.mode(PullUp);

count = 0; chk2=0; while(chk == 1) { if(chk2 == 1) { DRDY_BAR1.disable_irq(); printf("\n Reading and displaying buffer"); for(i=0;i<= 2500;i++) { printf("%f\n",(float)(adc_buff[i]*0.0000008654594421384)); printf("%d\n",adc_buff[i]); } printf("Reading Over"); chk=0; chk2 = 0; } else { count = count; togg = !togg; }

} }

for initial configurations void setup() { initially make all inputs low until power is up and stabilized CHIPSEL_BAR = 0; ADS_START = 0; RESET_BAR = 0; wait for oscillator to wake up wait(1);

CHIPSEL_BAR = 1; RESET_BAR = 1; wait for tpor time wait for power on reset wait(1); RESET_BAR = 0; send a reset pulse and wait for t_reset amount of time wait(1); RESET_BAR = 1;release the reset Wait for 18 tclks = 36 us wait_us(36);

Device wakes up in RDATAC mode so send SDATAC command to write to registers cmdWrite(CMD_SDATAC) ; printf("Device is in SDATAC mode\n");

regRead(REG_ID); printf("DEVICE ID register read from ADS is= 0x%X\n",data1); wait(1);

Since we are using internal 2.42V reference and enable clock on the CLK PIN Write 0xA8 to CONFIG2 register regWrite(REG_CONFIG2,0xA8);

Set continuous sampling mode, 500 SPS regWrite(REG_CONFIG1,0x02);

PGA Gain = 6, inputs shorted for noise measurements regWrite(REG_CH1SET, 0x01);

read data from CONFIG2 register regRead(REG_CONFIG2); printf("REG_CONFIG2 register read from ADS for initial setup is= 0x%X\n",data1);

read data from CONFIG1 register regRead(REG_CONFIG1); printf("REG_CONFIG1 register read from ADS for initial setup is= 0x%X\n",data1);

read data from CONFIG1 register regRead(REG_CH1SET); printf("REG_CH1SET register read from ADS for initial setup is= 0x%X\n",data1); }

void testsetup() { Send SDATAC command to write to registers to set test signals cmdWrite(CMD_SDATAC) ; printf("Device is in SDATAC mode\n");

Since we are using internal 2.42V reference and enable clock on the CLK PIN Write 0xA3 to CONFIG2 register to set test signal and its freq = 1Hz regWrite(REG_CONFIG2,0xA3);

PGA Gain = 6, test signal selected regWrite(REG_CH1SET, 0x05);

read data from CONFIG2 register regRead(REG_CONFIG2); printf("REG_CONFIG2 register read from ADS for test signal setup is= 0x%X\n",data1);

read data from CONFIG1 register regRead(REG_CH1SET); printf("REG_CH1SET register read from ADS for test signal setup is= 0x%X\n",data1); }

void ecgsetup() { cmdWrite(CMD_SDATAC) ; Set to SDATAC mode to set CH1SET register

regWrite(REG_CONFIG1,0x02); regWrite(REG_CONFIG2, 0xE0);put INT_TEST and TEST_FREQ bits to default mode(set those bits to '0') regWrite(REG_LOFF, 0xF0); regWrite(REG_CH1SET, 0x00); Set to read normal electrode input regWrite(REG_RLD_SENS, 0x23);Set RLD_SENS regWrite(REG_LOFF_SENS, 0x03);Set LOFF_SENS regWrite(REG_MISC1, 0x02);Set RESP1 regWrite(REG_MISC2, 0x03);Set RESP2 printf("connect ECG leads\n"); wait(0.5); regRead(REG_LOFF_STAT);Read LOFF_STAT register printf("REG_LOFF_STAT register read from ADS for ecg setup is= 0x%X\n",data1); }

void doHelp(void) { printf("=== spi test ===\n\r") ; printf("commands available\n\r") ; printf("help\n\r") ; printf("status\n\r") ; printf("freq freq_in_hz\n\r") ; printf("mode (0 | 1 | 2 | 3)\n\r") ; printf("bit (4 - 16)\n\r") ; printf("write value\n\r") ; printf("read\n\r") ; printf("loop number (set repeat number for read/write)\n\r") ; }

void doStatus(void) { printf("=== Status Report ===\n\r") ; printf("bits: %d\n\r", bits) ; printf("mode: %d\n\r", mode) ; printf("freq: %d Hz\n\r", freq) ; printf("loop: %d\n\r", loop) ; }

void doFreq(void) { int freq = 0 ; scanf("%d", &freq) ; printf("setting frequency to %d\n\r", freq) ; mySpi.frequency(freq) ; }

void doMode(void) { scanf("%d", &mode) ; printf("setting format(%d, %d)\n\r",bits, mode) ; mySpi.format(bits, mode) ; }

void doBit(void) { scanf("%d", &bits) ; printf("setting format(%d, %d)\n\r",bits, mode) ; mySpi.format(bits, mode) ; }

void doWrite(void) {

DRDY_BAR1.disable_irq();

CHIPSEL_BAR = 0; int freq1 = 50000; mySpi.frequency(freq1) ; value1 = mySpi.write(0x00); value2 = mySpi.write(0x00); value3 = mySpi.write(0x00); value4 = mySpi.write(0x00); value5 = mySpi.write(0x00); value6 = mySpi.write(0x00);

CHIPSEL_BAR = 0; DRDY_BAR1.enable_irq(); } void doWrite2(void) {

DRDY_BAR1.disable_irq(); DRDY_BAR1.disable_irq(); uint32_t adc_val; CHIPSEL_BAR = 0; int freq1 = 50000; mySpi.frequency(freq1) ; value1 = mySpi.write(0x00); value2 = mySpi.write(0x00); value3 = mySpi.write(0x00); value4 = mySpi.write(0x00); value5 = mySpi.write(0x00); value6 = mySpi.write(0x00); if(count<=2499) { adc_buff[count] = ((value4<< 16)|(value5 <<8) |(value6)); count = count + 1; } else { count = 0; chk2 = 1; } CHIPSEL_BAR = 0; DRDY_BAR1.enable_irq();

} void doRead(void) { int dummy = 0 ;

while(!DRDY_BAR) ADS_START = 0;

value = mySpi.write(dummy) ;

}

void doLoop(void) { scanf("%d", &loop) ; printf("repeat number has been set to %d\n\r", loop) ; }

void cmdWrite(int data) { CHIPSEL_BAR = 0; mySpi.write(data) ; wait_ms(1); CHIPSEL_BAR = 1; }

void regWrite(int address, int data) { int data_to_send = CMD_WREG << 5; data_to_send = data_to_send | address; CHIPSEL_BAR = 0; mySpi.write(data_to_send); wait_ms(1); mySpi.write(0x00) ; wait_ms(1); mySpi.write(data) ; wait_ms(1); CHIPSEL_BAR = 1; }

void regRead(int address) { int data_to_receive = CMD_RREG << 5; data_to_receive = data_to_receive | address; CHIPSEL_BAR = 0; mySpi.write(data_to_receive); wait_ms(1); mySpi.write(0x00) ; wait_ms(1); data1 = mySpi.write(0x00) ;

printf("DEVICE ID register read from ADS is= 0x%X\n",data1);

wait_ms(1); CHIPSEL_BAR = 1; }