On Fri, Jan 04, 2008 at 03:09:07PM -0800, Rick Altherr wrote: > If your switch is betwen PD0 and +5V, why do you need the pullups enabled? > That would make it always be +5V since when the switch is off, it would be > pulled up by the pull-ups.
Reading the datasheet, setting PORTD to zero should disable the pullups. To be sure, I tried adding a line to force it: MCUCR = _BV(PUD); This makes no difference. So, either I am not setting the pin's up properly. OR, I am not reading from them correctly. Or both. > So, every iteration through the loop, PD0 is checked to see if it is > 1. > Because of the above, it always is. Then, it toggles PC4. Depending > on > how fast the clock is going, this could easily be toggling at a rate > that > the naked eye cannot see. For a 1MHz part, it could take 4 cycles to > run > an iteration of the loop, so the LED would be toggling at 250KHz, or > stated > another way, would have a 50% duty cycle at 125KHz. That makes sense. Sticking a delay in the loop just makes it sit there and flash. J _______________________________________________ AVR-chat mailing list AVR-chat@nongnu.org http://lists.nongnu.org/mailman/listinfo/avr-chat
