PIC24FJ128GA110 programming for I2C

Question

I want to make a PIC24FJ128GA110 communicate via I2C on an ADC Maxim MAX11603. I am really new to PIC programming.

I tried to initialize the I2C2 bus (will join my functions) so I can get an SCL signal on my scope, but despite my initialization, it is not working. I checked the pull-ups resistors and their value is 3.3 ohms which is what I want. I reckon my problem would come from the clock configuration as I am really not sure about it.

Does someone have any ideas of what I could try to indeed have a SCL signal on my scope please?

#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
//#include "system.h"
#include "i2c.h"



#ifndef _XTAL_FREQ
#define _XTAL_FREQ  8000000UL
#endif

#ifndef FCY
#define FCY _XTAL_FREQ/2
#endif


#include <libpic30.h>

////////////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////////////

//We give a start condition on SDA and SCL
#define SDA TRISAbits.TRISA3
#define SCL TRISAbits.TRISA2 
#define SDA_IN PORTAbits.RA3
#define SCL_IN PORTAbits.RA2

#define I2C_WADDR(x) (x & 0xFE) //clear R/W 
#define I2C_RADDR(x) (x | 0x01) //set R/W


////////////////////////////////////////////////////////////////////////////////
//Timer and interrupt for i2c 
void myTimer() {
    //i2c2_init(100);
    T1CONbits.TON = 1;
    T1CONbits.TCS = 0;
    T1CONbits.TCKPS = 0b10;
    PR1 = 10000; // period to read I2C, This could probably be chosen more intelligently
    TMR1 = 0;
}

//Configuration of the oscillator
void init_OSC() {
    
    OSCCONbits.COSC = 0b001;
    OSCCONbits.NOSC = 0b001;
    // Configure PLL prescaler, PLL multiplier, and PLL postscaler
    CLKDIVbits.RCDIV = 0;  // PLL prescaler: N1 = 2
    CLKDIVbits.DOZE = 0; // PLL postscaler: N2 = 2
    
    // Configure oscillator selection bits
    __builtin_write_OSCCONH(0x01);  // Fast RC oscillator with PLL
    __builtin_write_OSCCONL(OSCCON | 0x01); // Enable clock switch
    
    // Wait for PLL to lock
    while (OSCCONbits.LOCK != 1) {}
    
}


//Function initiates I2C2 module to baud rate BRG
void i2c2_init(int BRG) {
    
    //I2C2ADD = 0b1101101;
    I2C2ADD = 0b00000001;
    I2C2BRG = BRG;
    
    //Enable open-drain mode on SDA2
    ODCAbits.ODA2 = 1;
    ODCAbits.ODA3 = 1;
    //Enable pull up for SCL and SDA
    CNPD3bits.CN35PDE = 1; //  SCL2 pin 
    CNPD3bits.CN36PDE = 1; // SDA2 pin
    
    SDA = 0;
    SCL = 0; 
    SCL_IN = SDA_IN = 0 ;
    
    I2C2CONbits.I2CEN = 0; // Disable I2C Mode
    // Clear Interrupt
    IFS3bits.MI2C2IF = 0;
    //Continue module operation in Idle mode
    I2C2CONbits.I2CSIDL = 0;
    //IPMIEN mode disabled
    I2C2CONbits.IPMIEN = 1;
    //7 bits slave address
    I2C2CONbits.A10M = 0;
    //Slew rate enabled
    I2C2CONbits.DISSLW = 1;
    //General call address disabled
    I2C2CONbits.GCEN = 0;
    //Disable SMBus input thresholds
    I2C2CONbits.SMEN = 1;
    //Software or receive call stretching disabled
    I2C2CONbits.STREN = 0;
    // Enable I2C Mode
    I2C2CONbits.I2CEN = 1;

}

//Function initiates a start condition on bus
void i2c2_start(void) {
    I2C2CONbits.ACKDT = 0; //Reset any previous Ack
    __delay_us(10);
    I2C2CONbits.SEN = 1; //Initiate Start condition
    SDA = 1;
    __delay_us(10);
    SCL = 1;
    __delay_us(10);
    SDA = 0;

}

void i2c2_restart(void) {
    I2C2CONbits.RSEN = 1; //Initiate restart condition
    __delay_us(10);
}


//Resets the I2C bus to Idle
void reset_i2c2_bus(void) {
    I2C2CONbits.PEN = 1; //initiate stop bit
    I2C2CONbits.RCEN = 0;
    IFS3bits.MI2C2IF = 0; // Clear Interrupt
    I2C2STATbits.IWCOL = 0;
    I2C2STATbits.BCL = 0;
    __delay_us(10);
}


//Basic I2C byte send
char send_i2c2_byte(int data) {
    IFS3bits.MI2C2IF = 0; // Clear Interrupt
    I2C2TRN = data; // load the outgoing data byte 
    // Check for NO_ACK from slave, abort if not found
    if (I2C2STATbits.ACKSTAT == 1) {
        reset_i2c2_bus();
        return (1);
    }
    __delay_us(10);
    return (0);
}

//Function that write
void I2C2write(char addr, char value) {
    i2c2_start();
    send_i2c2_byte(addr);
    send_i2c2_byte(value);
    reset_i2c2_bus();
}

//Function reads data, returns the read data, no ack
char i2c2_read(void) {
    char data = 0;
    i2c2_start();
    I2C2CONbits.RCEN = 1; //set I2C module to receive
    data = I2C2RCV; //get data from I2CRCV register
    return data; //return data
}


//function reads data, returns the read data, with ack

char i2c2_read_ack(void) {
    char data = 0;
    I2C2CONbits.RCEN = 1; //set I2C module to receive
    data = I2C2RCV; //get data from I2CRCV register
    I2C2CONbits.ACKEN = 1; //set ACK to high
    __delay_us(10); //wait before exiting  
    return data; //return data
}

Above is my i2c.c file

#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include "xc.h"
#include <p24FJ128GA110.h>

void myTimer();
void init_OSC();
void i2c2_init(int BRG);
void i2c2_start(void);
void i2c2_restart(void);
void reset_i2c2_bus(void);
char send_i2c2_byte(int data);
void I2C2write(char addr, char value);
char i2c2_read(void);
char i2c2_read_ack(void);

Above is my i2c.h file

#include <stdio.h>
#include <stdlib.h>
#include "i2c.h"



#define ADC_SLAVE_ADDRESS_WRITE  0b11001010
#define ADC_SLAVE_ADDRESS_READ  0b11001011
#define SETUP_REGISTER_ADDRESS 0b11001101
#define CONFIGURATION_REGISTER_ADDRESS 0b01101010

/*
 * 
 */
int main() {
    //myTimer();
    init_OSC();
    i2c2_init(0x27);

    while (1) {
        //i2c2_start();
        //send_i2c2_byte(ADC_SLAVE_ADDRESS_WRITE);
        //send_i2c2_byte(SETUP_REGISTER_ADDRESS);
        //reset_i2c2_bus();
    }
    return (EXIT_SUCCESS);
}

And this is my main file. As I said I'm new to this, I tried to implement the I2C library the best I could. Please if you have any comments about it, don't hesitate to let me know. Thank you very much.