18F258 Timers never overflow!

xben · Joined: 23 Jan 2004 Posts: 1

Hi..

got a little problem.. I try to use the Timers (0 & 1) in 16 bits. Their interrupts are ON, and the Global interrupts to.. but they never overflow!

When I debug the program an look at the TMR0L/TMR0H & TMR1L/TMR1H, I see the LOW registers moving from 0 to FF and that's ALL.. the high registers don't move.. so the interrupts never come. :(

thanks!

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

It's possible that you could have a problem with Timer0, because it
can be configured in either 8-bit or 16-mode for that PIC.

But Timer1 is always 16 bits, so it's unlikely that it can't increment
the MSB.

It's my guess that something else is going on. I think the most likely
thing is this:

You may not be displaying the Timer MSB properly. You need to
use "%LX" in printf() to display a 16 or 32 bit value in CCS.
If you only use "%X", you won't see the MSB displayed.