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#pragma once
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <linux/i2c.h>
#include <linux/i2c-dev.h>
#include <cstdint>
#include <string>
class sensorI2C {
//Predominantly used for I2C handler functions; implement high-level functions in sensor classes
//Implemented as a combination of Jazz' implementation and Derek Malloy's code
public:
//Initial single byte write, used at beginning of read operation
//Returns 0 if successful, -1 if not
int initialWrite(unsigned char registerAddress) {
unsigned char *convertedAddressBuffer = new unsigned char[1];
convertedAddressBuffer[0] = registerAddress;
//Expect 1 byte response from 1 byte write
if (write(i2c_bus, convertedAddressBuffer, 1) != 1) {
fprintf(stderr, "ERROR DOING INITIAL READ TRANSACTION WRITE TO REGISTER %x FOR DEVICE %x\n", registerAddress, deviceAddress);
return 0;
}
return 1;
}
int writeRegister(unsigned char registerAddress, unsigned char value) {
//initialWrite() not used here because it's easier to just pack it into one buffer for file writing
unsigned char writeBuffer[2];
writeBuffer[0] = registerAddress;
writeBuffer[1] = value;
//Expect 2 byte output
if (write(i2c_bus, writeBuffer, 2) != 2) {
//These error messages are kind of obtuse but I'd rather have too much information than not enough
fprintf(stderr, "ERROR WRITING %x TO REGISTER %x ON DEVICE %x\n", value, registerAddress, deviceAddress);
return -1;
}
return 0;
}
//Could probably be uint8_t but Derek Malloy does it with unsigned chars and that's what worked during testing so I don't want to touch it
unsigned char readSingleRegister(unsigned char registerAddress) {
printf("reg addr: %X\n", registerAddress);
initialWrite(registerAddress);
unsigned char* readBuffer = new unsigned char[1];
if (read(i2c_bus, readBuffer, 1) != 1){
fprintf(stderr, "FAILED TO READ VALUE FROM REGISTER %x ON DEVICE %x\n", registerAddress, deviceAddress);
return -1;
}
printf("readBuffer: %X\n", readBuffer[0]);
return readBuffer[0];
}
unsigned char* readMultipleRegisters(unsigned char startingRegisterAddress, int numberOfRegisters) {
initialWrite(startingRegisterAddress);
unsigned char* readBuffer = new unsigned char[numberOfRegisters];
if (read(i2c_bus, readBuffer, numberOfRegisters) != numberOfRegisters) {
fprintf(stderr, "ERROR TRYING TO READ %d REGISTERS STARTING AT ADDRESS %x ON DEVICE %x\n",
numberOfRegisters, startingRegisterAddress, deviceAddress);
}
return readBuffer;
}
//Intakes device address and file
//Private because IT'S ASSUMED PROGRAMMER WILL CALL THIS METHOD DURING INIT() ROUTINE
int setupI2C(std::string I2C_FILE) {
// Open i2c driver file
i2c_bus = open("/dev/i2c-2", O_RDWR);
if(i2c_bus < 0){
fprintf(stderr, "FAILED TO OPEN I2C BUS USING FILE %s\n", "/dev/i2c-2");
close(i2c_bus);
return -1;
}
// Identify slave device address (MODIFIED FROM INITIAL IMPLEMENTATION, USES INTERNAL deviceAddress INSTEAD OF PARAMETER)
if(ioctl(i2c_bus, I2C_SLAVE, deviceAddress) < 0){
fprintf(stderr, "FAILED TO CONNECT TO DEVICE AT ADDRESS %x VIA I2C\n", deviceAddress);
close(i2c_bus);
return -1;
}
return 0;
}
/**
* @brief Initialize the sensor.
*
* @param data Data for initializing the sensor
*
* @return true Initialization Success
* @return false Initialization Failure
*/
virtual bool init() = 0;
unsigned char deviceAddress;
int i2c_bus;
std::string I2C_FILE;
};
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