PIC24 – testing I2C module dead/alive

i2cpic

I got PIC24FJ192GB106 (64 pin package) and I cannot get the I2C module working at all. What is the easiest and most straight forward way of testing, whether the module is OK?

I am using I2C1 module, (SCL1 – pin 44, SDA1 – pin 43).

BRG register = 39; // 100 kHz for Fosc = 8 MHz

// Control register
    I2C1CONbits.I2CEN = 1;    
    I2C1CONbits.I2CSIDL = 0;   
    I2C1CONbits.SCLREL = 1; 
    I2C1CONbits.IPMIEN = 0;   
    I2C1CONbits.A10M = 0;    
    I2C1CONbits.DISSLW = 1;   
    I2C1CONbits.SMEN = 0;     
    I2C1CONbits.GCEN = 0;   
    I2C1CONbits.STREN = 0;   
    I2C1CONbits.ACKDT = 0;    
    I2C1CONbits.ACKEN = 0;   
    I2C1CONbits.RCEN = 0;   
    I2C1CONbits.PEN = 0;
    I2C1CONbits.RSEN = 0;      
    I2C1CONbits.SEN = 0;


// starting the module
I2C1CONbits.I2CEN = 1;

// setting the START CONDITION
I2C1CONbits.SEN = 1;

There is no response. The Start Condition is not executed. The I2C pheripheral is on NON-remappable pins. Whole TrisD register (pin 43 = D9, pin 44 = D10) is set as input (after reset). The pins has pull-ups (3.3 V, 4.7 kOhm). I have also tried to set corresponding bit in ODCD to 1 (digital pin), and 0 (open drain).

Have I missed something?
Microcontroller is working fine (UART, PWM, reference clock, ADC, …).

I would appriciate any guidance.

Best Answer

Go the hard way.

Write the test routine for sending start or stop bits and put it in a while loop.

Your main code will look like this.

main
{
initialize i2c();//Configure the I2C module in this function
while(1)
{
 i2c_send(); //Learn how the I2C transmits data and send the data   accordingly.
}

}

Now take an oscilloscope and observe the wave forms.

If have not messed up with configurations or initializations you will see the magic waves.

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