Dear Sir,
Thank you a lot! I am really disappointing to write SPI code. I am a new arduino user.
Sorry for not able to attach big file. This is the datasheet link.
http://www.analog.com/media/en/technical-documentation/data-sheets/ADAS1000_1000-1_1000-2.pdf
It looks related register configuration is tough. One reference could give an idea,
http://www.mit.edu/~gari/CODE/ECG_lab/ecg_ads1292.ino
- What would be the buffer writing ?
2.How to configure DRDY?
3.It needs interrupt?
Kindly look at this code,
Circuit:
ADAS1000 ecg board attached to pins 6, 7, 10 - 13:
DRDY: pin 6
CSB: pin 7
MOSI: pin 11
MISO: pin 12
SCK: pin 13
// SPI
#define DOUT 11 //MOSI
#define DIN 12 //MISO
#define SPICK 13 //SCK
// pins
#define PIN_CS 10
#define PIN_DRDY 6
#include <SPI.h>
//ADAS1000's memory register addresses:
const int LEADONE_LA = 0x11; //3 most significant bits of left arm ECG
const int LEADTWO_LL = 0x12; //16 least significant bits of left leg ECG
const byte READ = 0x40 ; // ADAS1000's read command
const byte WRITE =0x81F804AE; // ADAS1000's write command
// pins used for the connection with ecg device
// initialization the data ready and chip select pins:
pinMode(SPICK, OUTPUT);
pinMode(DIN, INPUT);
pinMode(DOUT, OUTPUT);
pinMode(PIN_LED, OUTPUT);
pinMode(PIN_CS, OUTPUT);
pinMode(PIN_RESET, OUTPUT);
pinMode(PIN_START, OUTPUT);
pinMode(PIN_DRDY, INPUT);
digitalWrite(PIN_CS, HIGH);
digitalWrite(PIN_START, LOW);
delay(0.50);
}
void setup() {
Serial.begin(9600);
// start the SPI library:
SPI.begin();
//the important parmiter for SPI communication
// spi data mode
// sets clock polarity and phase
// CPOL = 0 (clock polarity, clock is idle when low)
// CPHA = 1 (clock phase , data is shifted in and out on the rising of the data clock signal )
SPI.setDataMode(SPI_MODE1);
// spi clock divider
// sets relative to the system clock
// n transitions per cycles (SPI_CLOCK_DIV2 = 1 transition / 2 cycles)
// DIV4 is arduino default, override to make faster
// needs to be at least 32, or the clock is too slow, 64 to be safe
SPI.setClockDivider(SPI_CLOCK_DIV16);
// spi bit order
// sets the order of the bits shifted in and out
// MSBFIRST = most-significant bit first
SPI.setBitOrder(MSBFIRST);
//Setting of DRDY for interrupt service routine
int pin = 6;
volatile int state = LOW;
void setup() {
pinMode(6, OUTPUT);
attachInterrupt(digitalPinToInterrupt(pin), blink, CHANGE);
}
void loop() {
digitalWrite(pin, state);
}
void blink() {
state = !state;
}
// don't do anything until the data ready pin is high:
if (digitalRead(PIN_CS) == HIGH) {
//Read the ss data
int LEADONE_LA= readRegister(0x11, 2);
Serial.print("left arm ECG=");
Serial.print(left arm ECG);
//Read the pressure data highest 3 bits:
byte pressure_data_high = readRegister(0x1F, 1);
pressure_data_high &= 0b00000111; //you only needs bits 2 to 0
//Read the pressure data lower 16 bits:
unsigned int pressure_data_low = readRegister(0x20, 2);
//combine the two parts into one 19-bit number:
long pressure = ((pressure_data_high << 16) | pressure_data_low) / 4;
// display the temperature:
Serial.println("\tPressure [Pa]=" + String(pressure));
}
}
//Read from or write to register from the ADAS1000:
unsigned int readRegister(byte thisRegister, int bytesToRead ) {
byte inByte = 0; // incoming byte from the SPI
unsigned int result = 0; // result to return
Serial.print(thisRegister, BIN);
Serial.print("\t");
// SCP1000 expects the register name in the upper 6 bits
// of the byte. So shift the bits left by two bits:
thisRegister = thisRegister << 2;
// now combine the address and the command into one byte
byte dataToSend = thisRegister & READ;
Serial.println(thisRegister, BIN);
// take the chip select low to select the device:
digitalWrite(chipSelectPin, LOW);
// send the device the register you want to read:
SPI.transfer(dataToSend);
// send a value of 0 to read the first byte returned:
result = SPI.transfer(0x00);
// decrement the number of bytes left to read:
bytesToRead--;
// if you still have another byte to read:
if (bytesToRead > 0) {
// shift the first byte left, then get the second byte:
result = result << 8;
inByte = SPI.transfer(0x00);
// combine the byte you just got with the previous one:
result = result | inByte;
// decrement the number of bytes left to read:
bytesToRead--;
}
// take the chip select high to de-select:
digitalWrite(chipSelectPin, HIGH);
// return the result:
return(result);
}
//Sends a write command to ADAS1000
void writeRegister(byte thisRegister, byte thisValue) {
// SCP1000 expects the register address in the upper 6 bits
// of the byte. So shift the bits left by two bits:
thisRegister = thisRegister << 2;
// now combine the register address and the command into one byte:
byte dataToSend = thisRegister | WRITE;
// take the chip select low to select the device:
digitalWrite(chipSelectPin, LOW);
SPI.transfer(dataToSend); //Send register location
SPI.transfer(thisValue); //Send value to record into register
// take the chip select high to de-select:
digitalWrite(chipSelectPin, HIGH);
}
