Ethan Harstad / I2CHelper

A helper class for I2C

Dependents:   MPU9150

I2CHelper.cpp@1:e1b13a0c1987, 2014-06-08 (annotated)

Committer:
ethanharstad
Date:
Sun Jun 08 00:05:20 2014 +0000
Revision:
1:e1b13a0c1987
Parent:
0:e0f604f504c4
Child:
2:51de41e0e0c9
Untested implementation

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ethanharstad 0:e0f604f504c4 1 #include "I2CHelper.h"
ethanharstad 0:e0f604f504c4 2
ethanharstad 0:e0f604f504c4 3 /* Constructors */
ethanharstad 0:e0f604f504c4 4 I2CHelper::I2CHelper() : i2c_(I2C_SDA, I2C_SCL) {}
ethanharstad 0:e0f604f504c4 5
ethanharstad 0:e0f604f504c4 6 I2CHelper::I2CHelper(PinName sda, PinName scl) : i2c_(sda, scl) {}
ethanharstad 0:e0f604f504c4 7
ethanharstad 0:e0f604f504c4 8
ethanharstad 0:e0f604f504c4 9 /* Read Functions */
ethanharstad 0:e0f604f504c4 10 bool I2CHelper::readBit(const uint8_t devAddr, const uint8_t regAddr, const uint8_t bit, uint8_t *data) {
ethanharstad 1:e1b13a0c1987 11 uint8_t buf;
ethanharstad 1:e1b13a0c1987 12 i2c_.write((int)(devAddr << 1), (char *)&regAddr, 1, true);
ethanharstad 1:e1b13a0c1987 13 i2c_.read((int)(devAddr << 1), (char *)&buf, 1);
ethanharstad 1:e1b13a0c1987 14 *data = buf & (1 << bit);
ethanharstad 1:e1b13a0c1987 15 return true;
ethanharstad 0:e0f604f504c4 16 }
ethanharstad 0:e0f604f504c4 17
ethanharstad 0:e0f604f504c4 18 bool I2CHelper::readBits(const uint8_t devAddr, const uint8_t regAddr, const uint8_t startBit, const uint8_t length, uint8_t *data) {
ethanharstad 1:e1b13a0c1987 19 uint8_t buf;
ethanharstad 1:e1b13a0c1987 20 i2c_.write((int)(devAddr << 1), (char *)&regAddr, 1, true);
ethanharstad 1:e1b13a0c1987 21 i2c_.read((int)(devAddr << 1), (char *)&buf, 1);
ethanharstad 1:e1b13a0c1987 22 buf >>= (startBit - length + 1);
ethanharstad 1:e1b13a0c1987 23 buf &= ((1 << length) - 1);
ethanharstad 1:e1b13a0c1987 24 *data = buf;
ethanharstad 1:e1b13a0c1987 25 return true;
ethanharstad 0:e0f604f504c4 26 }
ethanharstad 0:e0f604f504c4 27
ethanharstad 0:e0f604f504c4 28 bool I2CHelper::readByte(const uint8_t devAddr, const uint8_t regAddr, uint8_t *data) {
ethanharstad 0:e0f604f504c4 29 return readBytes(devAddr, regAddr, data, 1);
ethanharstad 0:e0f604f504c4 30 }
ethanharstad 0:e0f604f504c4 31
ethanharstad 0:e0f604f504c4 32 bool I2CHelper::readBytes(const uint8_t devAddr, const uint8_t regAddr, uint8_t *data, const uint8_t length) {
ethanharstad 1:e1b13a0c1987 33 i2c_.write((int)(devAddr << 1), (char *)&regAddr, 1, true);
ethanharstad 1:e1b13a0c1987 34 return i2c_.read((int)(devAddr << 1), (char *)data, (int)length);
ethanharstad 0:e0f604f504c4 35 }
ethanharstad 0:e0f604f504c4 36
ethanharstad 0:e0f604f504c4 37 /* Write Functions */
ethanharstad 0:e0f604f504c4 38 bool I2CHelper::writeBit(const uint8_t devAddr, const uint8_t regAddr, const uint8_t bit, const uint8_t data) {
ethanharstad 1:e1b13a0c1987 39 uint8_t buf;
ethanharstad 1:e1b13a0c1987 40 i2c_.write((int)(devAddr << 1), (char *)&regAddr, 1, true);
ethanharstad 1:e1b13a0c1987 41 i2c_.read((int)(devAddr << 1), (char *)&buf, 1, true);
ethanharstad 1:e1b13a0c1987 42 buf = (data != 0) ? (buf | (1 << bit)) : (buf & ~(1 << bit));
ethanharstad 1:e1b13a0c1987 43 i2c_.write((int)(devAddr << 1), (char *)&buf, 1);
ethanharstad 1:e1b13a0c1987 44 return true;
ethanharstad 0:e0f604f504c4 45 }
ethanharstad 0:e0f604f504c4 46
ethanharstad 0:e0f604f504c4 47 bool I2CHelper::writeBits(const uint8_t devAddr, const uint8_t regAddr, const uint8_t startBit, const uint8_t length, const uint8_t data) {
ethanharstad 1:e1b13a0c1987 48 uint8_t buf;
ethanharstad 1:e1b13a0c1987 49 i2c_.write((int)(devAddr << 1), (char *)&regAddr, 1, true);
ethanharstad 1:e1b13a0c1987 50 i2c_.read((int)(devAddr << 1), (char *)&buf, 1, true);
ethanharstad 1:e1b13a0c1987 51 uint8_t dat = data << (startBit - length + 1);
ethanharstad 1:e1b13a0c1987 52 uint8_t mask = ((1 << length) - 1) << (startBit - length + 1);
ethanharstad 1:e1b13a0c1987 53 dat &= mask;
ethanharstad 1:e1b13a0c1987 54 buf &= ~mask;
ethanharstad 1:e1b13a0c1987 55 buf |= dat;
ethanharstad 1:e1b13a0c1987 56 i2c_.write((int)(devAddr << 1), (char *)&buf, 1);
ethanharstad 1:e1b13a0c1987 57 return true;
ethanharstad 0:e0f604f504c4 58 }
ethanharstad 0:e0f604f504c4 59
ethanharstad 0:e0f604f504c4 60 bool I2CHelper::writeByte(const uint8_t devAddr, const uint8_t regAddr, const uint8_t data) {
ethanharstad 0:e0f604f504c4 61 return writeBytes(devAddr, regAddr, &data, 1);
ethanharstad 0:e0f604f504c4 62 }
ethanharstad 0:e0f604f504c4 63
ethanharstad 0:e0f604f504c4 64 bool I2CHelper::writeBytes(const uint8_t devAddr, const uint8_t regAddr, const uint8_t *data, const uint8_t length) {
ethanharstad 1:e1b13a0c1987 65 i2c_.start();
ethanharstad 1:e1b13a0c1987 66 i2c_.write((int)(devAddr << 1));
ethanharstad 1:e1b13a0c1987 67 i2c_.write((int)regAddr);
ethanharstad 1:e1b13a0c1987 68 for(int i = 0; i < length; i++) {
ethanharstad 1:e1b13a0c1987 69 i2c_.write(data[i]);
ethanharstad 1:e1b13a0c1987 70 }
ethanharstad 1:e1b13a0c1987 71 i2c_.stop();
ethanharstad 1:e1b13a0c1987 72 return true;
ethanharstad 0:e0f604f504c4 73 }