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MCP3424.cpp
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MCP3424.cpp
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/*
* Copyright (C) 2014 Bernhard Schneider <[email protected]>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* version 3 as published by the Free Software Foundation.
*
*/
#include <Arduino.h>
#include <MCP3424.h>
MCP3424::MCP3424 (uint8_t address): addr(address) { }
MCP3424::MCP3424 (PinType adr0, PinType adr1): addr(pin_addr[adr0*3+adr1]) {}
uint8_t MCP3424::generalCall(GCall_t call) const {
Wire.beginTransmission(0x00);
Wire.write(call);
return Wire.endTransmission();
}
uint8_t MCP3424::writeConfReg(Channel ch) {
cwrite.reg = creg[ch].reg;
Wire.beginTransmission(addr);
Wire.write(cwrite.reg);
return Wire.endTransmission();
}
uint8_t MCP3424::startNewConversion(Channel ch) {
creg[ch].bits.rdy = 1;
return writeConfReg(ch);
}
/* tries to find the highest gain */
Gain MCP3424::findGain(double value) const {
uint8_t g;
value = abs(value);
for(g = GAINx1; g <= GAINx8; g++)
if (value * (1<<(g+1)) >= 2.048)
return (Gain)g;
return GAINx8;
}
ConvStatus MCP3424::read(Channel ch, double& value, bool blocking) {
if (blocking == false)
return nb_read(ch, value);
ConvStatus err;
uint32_t t0 = millis();
do {
if ( (millis() - t0) > (conv_time[creg[ch].bits.res]) )
return R_TIMEOUT;
err = nb_read(ch, value);
} while (err == R_IN_PROGRESS);
return err;
}
ConvStatus MCP3424::nb_read(Channel ch, double & value) {
int32_t lval;
uint8_t b2, b3, b4;
if (cwrite.reg != creg[ch].reg)
if (creg[ch].bits.cmode == CONTINUOUS)
writeConfReg(ch);
else
startNewConversion(ch);
Wire.requestFrom(addr, (uint8_t)((cwrite.bits.res == R18B)?4:3));
if (Wire.available() < ((cwrite.bits.res == R18B)?4:3))
return R_I2C;
b2 = Wire.read();
b3 = Wire.read();
if (creg[ch].bits.res == R18B)
b4 = Wire.read();
cread.reg = Wire.read();
Wire.endTransmission();
if (cread.bits.rdy == 1)
return R_IN_PROGRESS;
if (cread.bits.res == R18B) {
lval = ((long)b2 << 24 | b3 << 16 | b4 << 8) >> 8;
} else {
lval = (b2 << 8) | b3;
}
value = 0.001 * lval / (1 << (cread.bits.res << 1)) / ( 1 << cread.bits.pga);
if (value > 2.048) return R_OVERFLOW;
if (value < -2.048) return R_UNDERFLOW;
return R_OK;
}