14.5.1 Application Use of IOIM

The setup in code example is used to showcase the general application of IOIM. The reference pin will be in output configuration and feedback will be input. The delay between the signal leaving the reference pin and being received in the feedback pin is taken into consideration using the blanking timer.

Figure 14-7. General IOIM Application

#include "xc.h"

int main(void) 
{
    IOIM1CONbits.ON = 0;                 // module is turned off.
    IOIM1STAT = 0;                       // clearing all status flags
    
    // both of the above steps clears the module status bits.
    
    IOIM1CONbits.TESTEN = 0x00;         // set 00/01 to disable artificial test.
    IOIM1BCONbits.BLANK = 100; // set to make sure the required delay is given between reference and feedback.
    
    IOIM1CONbits.REFSEL = 8;            // this is according to datasheet (pin rc8)
    IOIM1CONbits.FBKSEL = 7;            // this is according to datasheet (pin rc7)
    IOIM1CONbits.EOVFVAL = 10;          // set err count overflow value
    
    _IOM1IF = 0;                        // clear interrupt flag
    _IOM1IE = 1;                        // enable interrupt
    
    _TRISC8 = 0;                        // set the reference pin to output
    _LATC8 = 0;                         // set the reference pin value
    
    IOIM1CONbits.ON = 1;                // module is turned on
    
    while(1);
    
    return 0;
}

void __attribute__((interrupt, no_auto_psv)) _IOIM1Interrupt(void) 
{
   
    _IOM1IF = 0;                        // clear interrupt flag
    IOIM1STATbits.ERR = 0;
    if(IOIM1STATbits.OVF)
    {
        IOIM1STATbits.OVF = 0;
        // your overflow application code goes here
    }
}