Hi all

I am using an LPC925 with the KBI functions and whilst I have read the threads on here and looked around suitably, I cannot for the life of me figure out what is going on.

basically I can trigger a Keypad Interrupt no problem, and I can poll my IO to see which port triggered the interrupt.

The issue I have is that I can NEVER clear the Keypad interrupt flag. so after the interrupt has fired once, it will continue to keep firing even when the IO has reverted to the inactive state.

I have tried:
1, changing the pattern
2, changing the mask (this will stop it but how can I determine when the next KBI is fired?)
3, disable the EKBI = 0; then clear KBCON &=0xFE then set EKBI = 1;


plus a whole series of other useless attempts.

Basically what I want to do is increment a counter on when any of 4 inputs is active.


here is the relevant code

void keypad_init (void)
{
  // define pattern
  KBPATN = 0x4E;
  // define P0 pins that trigger interrupt
  KBMASK = 0x4E; 
  // pattern must not match
  KBCON = 0x00;

  // set P0 pins as inputs
  //P0M1 |= 0x4E;
  //P0M2 &= ~0x4E;

  // set isr priority to 0
  IP1 &= 0xFD;
  IP1H &= 0xFD;

  // enable keypad interrupt
  EKBI = 1;
}

This is in the interrupt routine

void keypad_isr(void) interrupt 7 using 1
{
    unsigned char mask = 0x01;
    unsigned char index;
    bit test;

	CurrentState = P0 & 0x4E;
	
	
   if (WorkingState != CurrentState){                 //Compare the inputs with what we had last time around
       //if something has changed we need to determine which its have changed
       WorkingState ^= CurrentState;
       for (index = 0; index <= 7 ; index++){
	       test = WorkingState & mask;         			//copy the bit to the test bit
          if (test== 1)digital_input_count[index]++;  //if the bit has changed then update then reset the debounce counter
          mask <<= 0x01;                              //shift the mask to the left 1 bit
       }//end for
   }//endif 
      

	WorkingState = CurrentState;
                                                      //update the workingstate with the current value
  KBPATN = P0 & 0x4E;											//change the pattern to reflect the new state
  																		//so we only get an interrupt when something changes
  																		
  // clear interrupt flag

  
  KBCON &= 0xFE;
  

}

Please no comments on coding style, commenting style, layout, or other stuff at the moment, it is horrible, I know, I am still fiddling around trying to get it going.


This is the same in the Emulator (Acqura) and the Simulator (Raisonance).

Any ideas.

Thanks Marshall