pimaster.cpp

#include <unistd.h>
#include <iostream>
#include <errno.h>
#include <math.h>
#include <stdint.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <asm/ioctl.h>
#include <wiringPiI2C.h>

#define	I2C_ADDRESS	0x40

// I2C definitions

#define I2C_SLAVE	0x0703
#define I2C_SMBUS	0x0720	/* SMBus-level access */

#define I2C_SMBUS_READ  1
#define I2C_SMBUS_WRITE 0

// SMBus transaction types

#define I2C_SMBUS_QUICK		    0
#define I2C_SMBUS_BYTE		    1
#define I2C_SMBUS_BYTE_DATA	    2 
#define I2C_SMBUS_WORD_DATA	    3
#define I2C_SMBUS_PROC_CALL	    4
#define I2C_SMBUS_BLOCK_DATA	    5
#define I2C_SMBUS_I2C_BLOCK_BROKEN  6
#define I2C_SMBUS_BLOCK_PROC_CALL   7		/* SMBus 2.0 */
#define I2C_SMBUS_I2C_BLOCK_DATA    8

// SMBus messages

#define I2C_SMBUS_BLOCK_MAX	32	/* As specified in SMBus standard */	
#define I2C_SMBUS_I2C_BLOCK_MAX	32	/* Not specified but we use same structure */

// Structures used in the ioctl() calls

union i2c_smbus_data
{
  uint8_t  byte ;
  uint16_t word ;
  uint8_t  block [I2C_SMBUS_BLOCK_MAX + 2] ;	// block [0] is used for length + one more for PEC
} ;

struct i2c_smbus_ioctl_data
{
  char read_write ;
  uint8_t command ;
  int size ;
  union i2c_smbus_data *data ;
} ;

static inline int i2c_smbus_access (int fd, char rw, uint8_t command, int size, union i2c_smbus_data *data)
{
  struct i2c_smbus_ioctl_data args ;

  args.read_write = rw ;
  args.command    = command ;
  args.size       = size ;
  args.data       = data ;
  return ioctl (fd, I2C_SMBUS, &args) ;
}

using namespace std;

/*
g++ pimaster.cpp -lwiringPi -o pimaster
*/

// read calibration data with correct LSB/MSB
uint16_t read16 (int fd, int reg)
{
  return (wiringPiI2CReadReg8 (fd, reg + 1) <<  8) | wiringPiI2CReadReg8 (fd, reg) ;
}


int setupComms()
{
  int fd ;

  fd = wiringPiI2CSetup (I2C_ADDRESS);

  return fd;
}

static int GetRegelaar(int fd)
{
/*
	int result = wiringPiI2CWrite (fd, 0x10);
	if(result == -1) return result;
	result = wiringPiI2CWrite (fd, 0x20);
	if(result == -1) return result;
	result = wiringPiI2CWrite (fd, 0x30);
	if(result == -1) return result;
*/
	// union i2c_smbus_data data
	// data.byte = 0x10;
	int data = 0x10;
	int result = i2c_smbus_access (fd, I2C_SMBUS_WRITE, data, I2C_SMBUS_BYTE, NULL) ;
	
	return result;
}

int main()
{
	int fd, result;
	fd = setupComms();
	if (fd<0)
	{
		cout << "Failed to setup device" << endl;
		return -1;
	}

	result = GetRegelaar(fd);
	cout << "GetRegelaar: 0x" << hex << result << endl;
}