I2Cdev.cpp

00001 // ported from arduino library: https://github.com/jrowberg/i2cdevlib
00002 // written by szymon gaertig (email: szymon@gaertig.com.pl, website: szymongaertig.pl)
00003 // Changelog:
00004 // 2013-01-08 - first release
00005 
00006 #include "I2Cdev.h"
00007 
00008 #define useDebugSerial
00009 
00010 I2Cdev::I2Cdev(): i2c(I2C_SDA,I2C_SCL)
00011 {
00012 
00013 }
00014 
00015 I2Cdev::I2Cdev(PinName i2cSda, PinName i2cScl): i2c(i2cSda,i2cScl)
00016 {
00017 
00018 }
00019 
00020 /** Read a single bit from an 8-bit device register.
00021  * @param devAddr I2C slave device address
00022  * @param regAddr Register regAddr to read from
00023  * @param bitNum Bit position to read (0-7)
00024  * @param data Container for single bit value
00025  * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
00026  * @return Status of read operation (true = success)
00027  */
00028 int8_t I2Cdev::readBit(uint8_t devAddr, uint8_t regAddr, uint8_t bitNum, uint8_t *data, uint16_t timeout) {
00029     uint8_t b;
00030     uint8_t count = readByte(devAddr, regAddr, &b, timeout);
00031     *data = b & (1 << bitNum);
00032     return count;
00033 }
00034 
00035 /** Read a single bit from a 16-bit device register.
00036  * @param devAddr I2C slave device address
00037  * @param regAddr Register regAddr to read from
00038  * @param bitNum Bit position to read (0-15)
00039  * @param data Container for single bit value
00040  * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
00041  * @return Status of read operation (true = success)
00042  */
00043 int8_t I2Cdev::readBitW(uint8_t devAddr, uint8_t regAddr, uint8_t bitNum, uint16_t *data, uint16_t timeout)
00044 {
00045     uint16_t b = 0;
00046     uint8_t count = readWord(devAddr, regAddr, &b, timeout);
00047     *data = b & (1 << bitNum);
00048     return count;
00049 }
00050 
00051 /** Read multiple bits from an 8-bit device register.
00052  * @param devAddr I2C slave device address
00053  * @param regAddr Register regAddr to read from
00054  * @param bitStart First bit position to read (0-7)
00055  * @param length Number of bits to read (not more than 8)
00056  * @param data Container for right-aligned value (i.e. '101' read from any bitStart position will equal 0x05)
00057  * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
00058  * @return Status of read operation (true = success)
00059  */
00060 int8_t I2Cdev::readBits(uint8_t devAddr, uint8_t regAddr, uint8_t bitStart, uint8_t length, uint8_t *data, uint16_t timeout) {
00061     // 01101001 read byte
00062     // 76543210 bit numbers
00063     //    xxx   args: bitStart=4, length=3
00064     //    010   masked
00065     //   -> 010 shifted
00066     uint8_t count, b;
00067     if ((count = readByte(devAddr, regAddr, &b, timeout)) != 0) {
00068         uint8_t mask = ((1 << length) - 1) << (bitStart - length + 1);
00069         b &= mask;
00070         b >>= (bitStart - length + 1);
00071         *data = b;
00072     }
00073     return count;
00074 }
00075 
00076 /** Read multiple bits from a 16-bit device register.
00077  * @param devAddr I2C slave device address
00078  * @param regAddr Register regAddr to read from
00079  * @param bitStart First bit position to read (0-15)
00080  * @param length Number of bits to read (not more than 16)
00081  * @param data Container for right-aligned value (i.e. '101' read from any bitStart position will equal 0x05)
00082  * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
00083  * @return Status of read operation (1 = success, 0 = failure, -1 = timeout)
00084  */
00085 int8_t I2Cdev::readBitsW(uint8_t devAddr, uint8_t regAddr, uint8_t bitStart, uint8_t length, uint16_t *data, uint16_t timeout) {
00086     // 1101011001101001 read byte
00087     // fedcba9876543210 bit numbers
00088     //    xxx           args: bitStart=12, length=3
00089     //    010           masked
00090     //           -> 010 shifted
00091     uint8_t count;
00092     uint16_t w;
00093     if ((count = readWord(devAddr, regAddr, &w, timeout)) != 0) {
00094         uint16_t mask = ((1 << length) - 1) << (bitStart - length + 1);
00095         w &= mask;
00096         w >>= (bitStart - length + 1);
00097         *data = w;
00098     }
00099     return count;
00100 }
00101 /** Read single byte from an 8-bit device register.
00102  * @param devAddr I2C slave device address
00103  * @param regAddr Register regAddr to read from
00104  * @param data Container for byte value read from device
00105  * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
00106  * @return Status of read operation (true = success)
00107  */
00108 int8_t I2Cdev::readByte(uint8_t devAddr, uint8_t regAddr, uint8_t *data, uint16_t timeout) {
00109     return readBytes(devAddr, regAddr, 1, data, timeout);
00110 }
00111 
00112 /** Read single word from a 16-bit device register.
00113  * @param devAddr I2C slave device address
00114  * @param regAddr Register regAddr to read from
00115  * @param data Container for word value read from device
00116  * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
00117  * @return Status of read operation (true = success)
00118  */
00119 int8_t I2Cdev::readWord(uint8_t devAddr, uint8_t regAddr, uint16_t *data, uint16_t timeout) {
00120     return readWords(devAddr, regAddr, 1, data, timeout);
00121 }
00122 
00123 /** Read multiple bytes from an 8-bit device register.
00124  * @param devAddr I2C slave device address
00125  * @param regAddr First register regAddr to read from
00126  * @param length Number of bytes to read
00127  * @param data Buffer to store read data in
00128  * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
00129  * @return Number of bytes read (-1 indicates failure)
00130  */
00131 int8_t I2Cdev::readBytes(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint8_t *data, uint16_t timeout)
00132 {
00133     char command[1];
00134     command[0] = regAddr;
00135     char *redData = (char*)malloc(length);
00136     i2c.write(devAddr<<1, command, 1, true);
00137     i2c.read(devAddr<<1, redData, length);
00138     for(int i =0; i < length; i++) {
00139         data[i] = redData[i];
00140     }
00141     free (redData);
00142     return length;
00143 }
00144 
00145 int8_t I2Cdev::readWords(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint16_t *data, uint16_t timeout)
00146 {
00147     return 0;
00148 }
00149 
00150 /** write a single bit in an 8-bit device register.
00151  * @param devAddr I2C slave device address
00152  * @param regAddr Register regAddr to write to
00153  * @param bitNum Bit position to write (0-7)
00154  * @param value New bit value to write
00155  * @return Status of operation (true = success)
00156  */
00157 bool I2Cdev::writeBit(uint8_t devAddr, uint8_t regAddr, uint8_t bitNum, uint8_t data) {
00158     uint8_t b;
00159     readByte(devAddr, regAddr, &b);
00160     b = (data != 0) ? (b | (1 << bitNum)) : (b & ~(1 << bitNum));
00161     return writeByte(devAddr, regAddr, b);
00162 }
00163 
00164 /** write a single bit in a 16-bit device register.
00165  * @param devAddr I2C slave device address
00166  * @param regAddr Register regAddr to write to
00167  * @param bitNum Bit position to write (0-15)
00168  * @param value New bit value to write
00169  * @return Status of operation (true = success)
00170  */
00171 bool I2Cdev::writeBitW(uint8_t devAddr, uint8_t regAddr, uint8_t bitNum, uint16_t data) {
00172     uint16_t w;
00173     readWord(devAddr, regAddr, &w);
00174     w = (data != 0) ? (w | (1 << bitNum)) : (w & ~(1 << bitNum));
00175     return writeWord(devAddr, regAddr, w);
00176 }
00177 
00178 /** Write multiple bits in an 8-bit device register.
00179  * @param devAddr I2C slave device address
00180  * @param regAddr Register regAddr to write to
00181  * @param bitStart First bit position to write (0-7)
00182  * @param length Number of bits to write (not more than 8)
00183  * @param data Right-aligned value to write
00184  * @return Status of operation (true = success)
00185  */
00186 bool I2Cdev::writeBits(uint8_t devAddr, uint8_t regAddr, uint8_t bitStart, uint8_t length, uint8_t data) {
00187     //      010 value to write
00188     // 76543210 bit numbers
00189     //    xxx   args: bitStart=4, length=3
00190     // 00011100 mask byte
00191     // 10101111 original value (sample)
00192     // 10100011 original & ~mask
00193     // 10101011 masked | value
00194     uint8_t b;
00195     if (readByte(devAddr, regAddr, &b) != 0) {
00196         uint8_t mask = ((1 << length) - 1) << (bitStart - length + 1);
00197         data <<= (bitStart - length + 1); // shift data into correct position
00198         data &= mask; // zero all non-important bits in data
00199         b &= ~(mask); // zero all important bits in existing byte
00200         b |= data; // combine data with existing byte
00201         return writeByte(devAddr, regAddr, b);
00202     } else {
00203         return false;
00204     }
00205 }
00206 
00207 /** Write multiple bits in a 16-bit device register.
00208  * @param devAddr I2C slave device address
00209  * @param regAddr Register regAddr to write to
00210  * @param bitStart First bit position to write (0-15)
00211  * @param length Number of bits to write (not more than 16)
00212  * @param data Right-aligned value to write
00213  * @return Status of operation (true = success)
00214  */
00215 bool I2Cdev::writeBitsW(uint8_t devAddr, uint8_t regAddr, uint8_t bitStart, uint8_t length, uint16_t data) {
00216     //              010 value to write
00217     // fedcba9876543210 bit numbers
00218     //    xxx           args: bitStart=12, length=3
00219     // 0001110000000000 mask byte
00220     // 1010111110010110 original value (sample)
00221     // 1010001110010110 original & ~mask
00222     // 1010101110010110 masked | value
00223     uint16_t w;
00224     if (readWord(devAddr, regAddr, &w) != 0) {
00225         uint8_t mask = ((1 << length) - 1) << (bitStart - length + 1);
00226         data <<= (bitStart - length + 1); // shift data into correct position
00227         data &= mask; // zero all non-important bits in data
00228         w &= ~(mask); // zero all important bits in existing word
00229         w |= data; // combine data with existing word
00230         return writeWord(devAddr, regAddr, w);
00231     } else {
00232         return false;
00233     }
00234 }
00235 
00236 /** Write single byte to an 8-bit device register.
00237  * @param devAddr I2C slave device address
00238  * @param regAddr Register address to write to
00239  * @param data New byte value to write
00240  * @return Status of operation (true = success)
00241  */
00242 bool I2Cdev::writeByte(uint8_t devAddr, uint8_t regAddr, uint8_t data) {
00243     return writeBytes(devAddr, regAddr, 1, &data);
00244 }
00245 
00246 /** Write single word to a 16-bit device register.
00247  * @param devAddr I2C slave device address
00248  * @param regAddr Register address to write to
00249  * @param data New word value to write
00250  * @return Status of operation (true = success)
00251  */
00252 bool I2Cdev::writeWord(uint8_t devAddr, uint8_t regAddr, uint16_t data) {
00253     return writeWords(devAddr, regAddr, 1, &data);
00254 }
00255 
00256 bool I2Cdev::writeBytes(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint8_t *data)
00257 {
00258     i2c.start();
00259     i2c.write(devAddr<<1);
00260     i2c.write(regAddr);
00261     for(int i = 0; i < length; i++) {
00262         i2c.write(data[i]);
00263     }
00264     i2c.stop();
00265     return true;
00266 }
00267 
00268 bool I2Cdev::writeWords(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint16_t *data)
00269 {
00270     return true;
00271 }
00272 
00273 uint16_t I2Cdev::readTimeout(void)
00274 {
00275     return 0;
00276 }