Elapsed Timer findings

[Tabsoft]

Very similar to what I did.
I used the Elapsed Timer to generate a 1KHz 50% duty cycle signal on PORTA.4.
I wanted to test the stability of the Timer1 interrupt period using the Elapsed Timer code we have been discussing.

In the ISR I used a call to the RELOAD_TIMER macro after setting the state of the pin.
That lets the Elapsed Timer code handle things and I could check the accuracy of the output.

I was lazy though and did not setup a variable to track the state of the pin.
I just read the port and flipped the pin.
This was a test and I really didn't mind if I hit the other pins on PORTA.

500ms Timer1 ISR:

        asm
            COMF PORTA, 0   ; 1 Tcy - Complement PORTA, Store in W
            ANDLW 10h         ; 1 Tcy - Force all PORTA pins to 0 except pin 4 
            MOVWF PORTA    ; 1 Tcy - Set the new value for PORTA
            RELOAD_TIMER    ;  Reload the timer
        endasm