BasicMicro - Forums

void interrupt My_interrupt(void) {

  if (/*PIR1.*/SSPIF == 1){                // I2C Interrupt
    if (/*SSPCON.*/SSPOV==1){
      j=SSPBUF; // Read address to clear buffer
      /*SSPCON.*/SSPOV=0;
    }
    else {
      if (/*SSPSTAT.*/START==1 && /*SSPSTAT.*/RW==0 && /*SSPSTAT.*/DA==0 && /*SSPSTAT.*/BF==1){state=1;} // State 1: MASTER WRITE, LAST BYTE WAS AN ADDRESS
      if (/*SSPSTAT.*/START==1 && /*SSPSTAT.*/RW==0 && /*SSPSTAT.*/DA==1 && /*SSPSTAT.*/BF==1){state=2;} // State 2: MASTER WRITE, LAST BYTE WAS DATA
      if (/*SSPSTAT.*/START==1 && /*SSPSTAT.*/RW==1 && /*SSPSTAT.*/DA==0 && /*SSPSTAT.*/BF==0){state=3;} // State 3: MASTER READ, LAST BYTE WAS AN ADDRESS
      if (/*SSPSTAT.*/START==1 && /*SSPSTAT.*/RW==1 && /*SSPSTAT.*/DA==1 && /*SSPSTAT.*/BF==0){state=4;} // State 4: MASTER READ, LAST BYTE WAS DATA
      if (/*SSPSTAT.*/START==1 && /*SSPSTAT.*/DA==1 && /*SSPSTAT.*/BF==0 && /*SSPSTAT.*/RW==0 && /*SSPCON.*/CKP==1){state=5;} // State 5: MASTER NACK

      switch ( state ) {
        case 1:
          j=SSPBUF; // Read address to clear buffer
          if (/*SSPCON.*/SSPOV==1){ //overflow?
            /*SSPCON.*/SSPOV=0;
            j=SSPBUF; // Read address to clear buffer
          }
          break;

        case 2:
          rxbuffer=SSPBUF; // Read DATA from master.
          if (/*SSPCON.*/SSPOV==1){ //overflow?
            /*SSPCON.*/SSPOV=0;
            rxbuffer=SSPBUF; // Read address to clear buffer
          }
          break;

        case 3:
          /*SSPCON.*/CKP =0; // Hold the SCL line low
          tx_data++;
          SSPBUF = tx_data; // load buffer with data to be sent to master
          /*SSPCON.*/CKP =1; // Release the SCL line
          j=SSPBUF; // read to empty buffer
          break;

        case 4:
          /*SSPCON.*/CKP =0; // Hold the SCL line low
          SSPBUF = tx_data; // load buffer with data to be sent to master
          /*SSPCON.*/CKP =1; // Release the SCL line
          j=SSPBUF; // read to empty buffer
          break;

        case 5:
          break;

        default : break;
      }
       j=SSPBUF; //clear buffer
    }
    /*PIR1.*/SSPIF = 0;                    // reset SSP interrupt flag
  } //I2C interrupt end
}

; simple test to loop I2c Outputs... to try to see what the Nano sees.
i2creg   var   byte
i2cval   var byte
i2cdatain var byte(4)

i2creg = 0
i2cval = 0

Main:
   toggle p12
   I2cout p0, p1, 0x42, [i2creg, i2cval]
   i2cval = i2cval + 1
   
   if i2creg >= 9 then
      i2creg = 0
      toggle p13   
      ; lets try reading several of them back...
      i2cout p0, p1, 0x42, [0]
      i2cin p0, p1, 0x42, [i2cdatain(0)]
      i2cin p0, p1, 0x42, [i2cdatain(1)]
;      i2cin p0, p1, 0x42, [i2cdatain(0), i2cdatain(1), i2cdatain(2), i2cdatain(3)]
      serout s_out, i9600, [hex i2cdatain(0), " ", hex i2cdatain(1), " ", hex i2cdatain(2), " ", hex i2cdatain(3), 13]
      pause 150
   else
      i2creg = i2creg + 1
   endif
   pause 25
   goto main