i2c.h

#include <xc.h>
#include <stdint.h>

// I2C Initialization function
void i2c_init() {
    // Set I2C pins as inputs
    TRISBbits.TRISB4 = 1;   // SCL pin
    TRISBbits.TRISB5 = 1;   // SDA pin
    
    // Configure I2C module
    SSP1CON1bits.SSPEN = 0;     // Disable MSSP module during configuration
    SSP1CON1bits.SSPM = 0b1000; // I2C Master mode, clock = Fosc / (4 * (SSP1ADD+1))
    SSP1ADD = 9;                // I2C clock = Fosc / (4 * (9+1)) = Fosc / 40
    
    SSP1CON1bits.SSPEN = 1;     // Enable MSSP module
}

// I2C Start condition
void i2c_start() {
    SSP1CON2bits.SEN = 1;    // Initiate Start condition
    while (SSP1CON2bits.SEN); // Wait for Start condition to complete
}

// I2C Stop condition
void i2c_stop() {
    SSP1CON2bits.PEN = 1;    // Initiate Stop condition
    while (SSP1CON2bits.PEN); // Wait for Stop condition to complete
}

// I2C Write function
void i2c_write(uint8_t data) {
    SSP1BUF = data;              // Write data to SSPBUF
    while (SSP1STATbits.BF);     // Wait for transmission to complete
    while (SSP1CON2bits.ACKSTAT); // Wait for ACK/NACK
}

// I2C Read function with ACK
uint8_t i2c_read_ack() {
    SSP1CON2bits.RCEN = 1;        // Enable receive mode
    while (!SSP1STATbits.BF);     // Wait for data reception
    uint8_t data = SSP1BUF;       // Read data from SSPBUF
    SSP1CON2bits.ACKDT = 0;       // Send ACK
    SSP1CON2bits.ACKEN = 1;       // Initiate ACK/NACK
    while (SSP1CON2bits.ACKEN);   // Wait for ACK/NACK to complete
    return data;
}

// I2C Read function with NACK
uint8_t i2c_read_nack() {
    SSP1CON2bits.RCEN = 1;        // Enable receive mode
    while (!SSP1STATbits.BF);     // Wait for data reception
    uint8_t data = SSP1BUF;       // Read data from SSPBUF
    SSP1CON2bits.ACKDT = 1;       // Send NACK
    SSP1CON2bits.ACKEN = 1;       // Initiate ACK/NACK
    while (SSP1CON2bits.ACKEN);   // Wait for ACK/NACK to complete
    return data;
}