triangle/v3/main/i2c.ino

64 lines
2.3 KiB
C++

/* Copyright (C) 2012 Kristian Lauszus, TKJ Electronics. All rights reserved.
This software may be distributed and modified under the terms of the GNU
General Public License version 2 (GPL2) as published by the Free Software
Foundation and appearing in the file GPL2.TXT included in the packaging of
this file. Please note that GPL2 Section 2[b] requires that all works based
on this software must also be made publicly available under the terms of
the GPL2 ("Copyleft").
Contact information
-------------------
Kristian Lauszus, TKJ Electronics
Web : http://www.tkjelectronics.com
e-mail : kristianl@tkjelectronics.com
*/
const uint8_t IMUAddress = 0x68; // AD0 is logic low on the PCB
const uint16_t I2C_TIMEOUT = 10; // Used to check for errors in I2C communication
uint8_t i2cWrite(uint8_t registerAddress, uint8_t data, bool sendStop) {
return i2cWrite(registerAddress, &data, 1, sendStop); // Returns 0 on success
}
uint8_t i2cWrite(uint8_t registerAddress, uint8_t *data, uint8_t length, bool sendStop) {
Wire.beginTransmission(IMUAddress);
Wire.write(registerAddress);
Wire.write(data, length);
uint8_t rcode = Wire.endTransmission(sendStop); // Returns 0 on success
if (rcode) {
Serial.print(F("i2cWrite failed: "));
Serial.println(rcode);
}
return rcode; // See: http://arduino.cc/en/Reference/WireEndTransmission
}
uint8_t i2cRead(uint8_t registerAddress, uint8_t *data, uint8_t nbytes) {
uint32_t timeOutTimer;
Wire.beginTransmission(IMUAddress);
Wire.write(registerAddress);
uint8_t rcode = Wire.endTransmission(false); // Don't release the bus
if (rcode) {
Serial.print(F("i2cRead failed: "));
Serial.println(rcode);
return rcode; // See: http://arduino.cc/en/Reference/WireEndTransmission
}
Wire.requestFrom(IMUAddress, nbytes, (uint8_t)true); // Send a repeated start and then release the bus after reading
for (uint8_t i = 0; i < nbytes; i++) {
if (Wire.available())
data[i] = Wire.read();
else {
timeOutTimer = micros();
while (((micros() - timeOutTimer) < I2C_TIMEOUT) && !Wire.available());
if (Wire.available())
data[i] = Wire.read();
else {
Serial.println(F("i2cRead timeout"));
return 5; // This error value is not already taken by endTransmission
}
}
}
return 0; // Success
}