First try at DT_INT's, I failed! help please!

[MOUNTAIN747]

OK, I have found out that it is returning from the interrupt. However I can not interrupt again for about ten seconds or the interrupt fails. A failure to interrupt forces another ten second delay before I can trigger again. Is there anything I can do to speed this process? On compile the program shows only 255 words long. I don’t understand this time delay before I can re enter the interrupt. Comments please…

[Darrel Taylor]

I’m using X1 board with 16F877A and pulsing RB0 with a wire lead.

That's the problem.

If you are using a wire to +5V, there's nothing to pull it back down.
The pin will hold a charge, and will slowly drain off, allowing it to re-trigger after a few seconds.

If you add a pull-down resistor it should work better.

Or, you can turn on PORTB pull-ups (OPTION_REG.7 = 0), make PORTB.4 LOW so you can use SW1 pushbutton.
Changing to OPTION_REG.6 = 0 will make it trigger on the falling edge (button press) instead of the rising edge (button release).

[MOUNTAIN747]

Thanks Darrel, I'll give it a try!

[MOUNTAIN747]

Yep! works great!

[Demon]

...
Or, you can turn on PORTB pull-ups (OPTION_REG.7 = 0), make PORTB.4 LOW so you can use SW1 pushbutton.
Changing to OPTION_REG.6 = 0 will make it trigger on the falling edge (button press) instead of the rising edge (button release).

This is funny, I did this very exercise yesterday and posted it in the Code Examples. LOL

Robert