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AD770x.cpp
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AD770x.cpp
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/*
* AD7705/AD7706 Library
* Kerry D. Wong
* http://www.kerrywong.com
* Initial version 1.0 3/2011
* Updated 1.1 4/2012
*/
#include "AD770X.h"
#include "SPI.h"
//write communication register
// 7 6 5 4 3 2 1 0
//0/DRDY(0) RS2(0) RS1(0) RS0(0) R/W(0) STBY(0) CH1(0) CH0(0)
void AD770X::setNextOperation(byte reg, byte channel, byte readWrite) {
byte r = 0;
r = reg << 4 | readWrite << 3 | channel;
digitalWrite(pinCS, LOW);
SPI.transfer(r);
digitalWrite(pinCS, HIGH);
}
//Clock Register
// 7 6 5 4 3 2 1 0
//ZERO(0) ZERO(0) ZERO(0) CLKDIS(0) CLKDIV(0) CLK(1) FS1(0) FS0(1)
//
//CLKDIS: master clock disable bit
//CLKDIV: clock divider bit
void AD770X::writeClockRegister(byte CLKDIS, byte CLKDIV, byte outputUpdateRate) {
byte r = CLKDIS << 4 | CLKDIV << 3 | outputUpdateRate;
r &= ~(1 << 2); // clear CLK
digitalWrite(pinCS, LOW);
SPI.transfer(r);
digitalWrite(pinCS, HIGH);
}
//Setup Register
// 7 6 5 4 3 2 1 0
//MD10) MD0(0) G2(0) G1(0) G0(0) B/U(0) BUF(0) FSYNC(1)
void AD770X::writeSetupRegister(byte operationMode, byte gain, byte unipolar, byte buffered, byte fsync) {
byte r = operationMode << 6 | gain << 3 | unipolar << 2 | buffered << 1 | fsync;
digitalWrite(pinCS, LOW);
SPI.transfer(r);
digitalWrite(pinCS, HIGH);
}
unsigned int AD770X::readADResult() {
digitalWrite(pinCS, LOW);
byte b1 = SPI.transfer(0x0);
byte b2 = SPI.transfer(0x0);
digitalWrite(pinCS, HIGH);
unsigned int r = b1 << 8 | b2;
return r;
}
double AD770X::readADResult(byte channel, float refOffset) {
while (!dataReady(channel)) {
};
setNextOperation(REG_DATA, channel, 1);
return readADResult() * 1.0 / 65536.0 * VRef - refOffset;
}
bool AD770X::dataReady(byte channel) {
setNextOperation(REG_CMM, channel, 1);
digitalWrite(pinCS, LOW);
byte b1 = SPI.transfer(0x0);
digitalWrite(pinCS, HIGH);
return (b1 & 0x80) == 0x0;
}
void AD770X::reset() {
digitalWrite(pinCS, LOW);
for (int i = 0; i < 100; i++)
SPI.transfer(0xff);
digitalWrite(pinCS, HIGH);
}
AD770X::AD770X(double vref) {
VRef = vref;
pinMode(pinMOSI, OUTPUT);
pinMode(pinMISO, INPUT);
pinMode(pinSPIClock, OUTPUT);
pinMode(pinCS, OUTPUT);
digitalWrite(pinCS, HIGH);
//SPCR = _BV(SPE) | _BV(MSTR) | _BV(CPOL) | _BV(CPHA) | _BV(SPI2X) | _BV(SPR1) | _BV(SPR0);
}
void AD770X::init(byte channel, byte clkDivider, byte polarity, byte gain, byte updRate) {
setNextOperation(REG_CLOCK, channel, 0);
writeClockRegister(0, clkDivider, updRate);
setNextOperation(REG_SETUP, channel, 0);
writeSetupRegister(MODE_SELF_CAL, gain, polarity, 0, 0);
while (!dataReady(channel)) {
};
}
void AD770X::init(byte channel) {
init(channel, CLK_DIV_1, BIPOLAR, GAIN_1, UPDATE_RATE_25);
}