// PIC18 in C - Versione 0.1a - Settembre 2014
// Copyright (c) 2014 VincenzoV.net
// Creative Commons | Attribuzione-Condividi allo stesso modo 3.0 Unported.
// Creative Commons | Attribution-Share Alike 3.0 Unported
// https://www.vincenzov.net/tutorial/PIC18/i2c-PLIB.htm

// I2C master - LM92

#define LM92_ADDR 0x4B
#define LM92_RES 0.0625       // Resolution (see LM92 data sheet)

#include "configurationbits.h"

#include <i2c.h>

void I2C_error_handler(int error_code); // Errors handler function

void main(void) // Program start here
{
    unsigned char i;
    int buffer[2];
    unsigned int data;
    double temperature;
    unsigned char addrRW;

    OSCCON = 0x70; // Set internal clock to 16 MHz
    SSPADD = 0x27; // Set 100 kHz clock ( @ 16 MHz )

    OpenI2C(MASTER, SLEW_ON); // I2C Master mode, Slew rate enabled

    IdleI2C(); // Wait until the bus is idle
    StartI2C(); // Send START condition

    addrRW = (LM92_ADDR << 1) | 0x01; // 7 bit address + R/W bit

    IdleI2C(); // Wait until the bus is idle
    if (WriteI2C(addrRW) < 0) // Send address with R/W set for read
        I2C_error_handler (-1); // Error in WriteI2C() documentation!

    IdleI2C(); // Wait until the bus is idle
    buffer[0] = ReadI2C(); // Read first byte of data
    AckI2C(); // Send ACK

    IdleI2C(); // Wait until the bus is idle
    buffer[1] = ReadI2C(); // Read nth byte of data
    AckI2C(); // Send ACK

    IdleI2C(); // Wait until the bus is idle
    StopI2C(); // Hang up, send STOP condition

    IdleI2C(); // Wait until the bus is idle
    CloseI2C();

    data = buffer[0]; // LM92 specific - See LM92 data sheet
    data = data << 8;

    data = data | buffer[1];
    data = data >> 3;
    temperature = LM92_RES * data; // Temperature in °C

    while (1);
}

void I2C_error_handler(int error_code) { // Error handler... emty
}