I2C_Sensor.cpp

00001 #include "I2C_Sensor.h"
00002 
00003 // calculate the 8-Bit write/read I2C-Address from the 7-Bit adress of the device
00004 #define GET_I2C_WRITE_ADDRESS(ADR)  (ADR << 1&0xFE) // ADR & 1111 1110
00005 #define GET_I2C_READ_ADDRESS(ADR)   (ADR << 1|0x01) // ADR | 0000 0001
00006 
00007 I2C_Sensor::I2C_Sensor(PinName sda, PinName scl, char i2c_address) : i2c_init(sda, scl), i2c(sda, scl), local("local")
00008 {
00009     I2C_Sensor::i2c_address = i2c_address;
00010     i2c_init.frequency(400000); // standard speed
00011     i2c.frequency(400000); // standard speed
00012     //i2c.frequency(1500000); // ultrafast!
00013 }
00014 
00015 void I2C_Sensor::saveCalibrationValues(float values[], int size, char * filename)
00016 {
00017     FILE *fp = fopen(strcat("/local/", filename), "w");
00018     for(int i = 0; i < size; i++)
00019         fprintf(fp, "%f\r\n", values[i]);
00020     fclose(fp);
00021 }
00022 
00023 void I2C_Sensor::loadCalibrationValues(float values[], int size, char * filename)
00024 {
00025     FILE *fp = fopen(strcat("/local/", filename), "r");
00026     for(int i = 0; i < size; i++)
00027         fscanf(fp, "%f", &values[i]);
00028     fclose(fp);
00029 }
00030 
00031 //--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
00032 // ATTENTION!!! there was a problem with other interrupts disturbing the i2c communication of the chip... that's why I use I2C to initialise the sonsors and MODI2C to get the data (only made with readMultiRegister)
00033 // IT DIDN'T WORK STABLE IN OTHER COMBINATIONS (if someone has an idea why please let me know)
00034 //--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
00035 
00036 char I2C_Sensor::readRegister(char reg)
00037 {
00038     char value = 0;
00039     
00040     i2c_init.write(i2c_address, &reg, 1);
00041     i2c_init.read(i2c_address, &value, 1);
00042 
00043     return value;
00044 }
00045 
00046 void I2C_Sensor::writeRegister(char reg, char data)
00047 {
00048     char buffer[2] = {reg, data};
00049     i2c_init.write(i2c_address, buffer, 2);
00050 }
00051 
00052 void I2C_Sensor::readMultiRegister(char reg, char* output, int size)
00053 {
00054     i2c.write (i2c_address, &reg, 1); // tell register address of the MSB get the sensor to do slave-transmit subaddress updating.
00055     i2c.read  (i2c_address, output, size); // tell it where to store the data read
00056 }