Erratic LED blinking

[Ioannis]

Thanks Jerson.

At the moment it looked OK to have the LCDout inside the regularly called ISR, as it updatetd the LCD often. If the freq is low enough 1-2 Hz, it updates every second the LCD because of the Pause commands.

Anyway, I moved the LCDout inside the Halfbridge sub and corrected the IF statement (<68 then freq=136). This helped much but not completely.

The final solution was to remove the ISR alltogether. Seems there is something fundamentally wrong with my ISR setup.

Ioannis

[HenrikOlsson]

In the ISR you have this:

    if seconds<1000 then
        seconds=seconds+1
    else
        seconds=0
        Timer0=0    'Stop timer0
        TMR0H=$C1   'Load Timer 0 with start value $C187
        TMR0L=$87   'to count up 16000 steps until rollover
        Timer0=1    'Start timer0

To me, this looks a bit strange - you're only reloading the TMR0 registers once every 1000 interrupts meaning that only the "first" period will be 1ms, then there will be 999 periods where the timer will freerun all the way from 0 to rollover.

[Ioannis]

Nice catch...

When someone shows you the stupid mistakes, its that moment you are embarrased a lot

Ioannis

[Ioannis]

And of course this explains the periodic error in the LED flashing...

Ioannis