topic Re: S12X Pulse Accumulator Troubles in S12 / MagniV Microcontrollers

S12X Pulse Accumulator Troubles

jamienicol — Tue, 03 Apr 2012 21:59:22 GMT

I'm trying to count pulses on an input pin using the pulse accumulator, but it's always saying there have been no pulses. I'm using a MC9S12XEP100. My initialisation code is this:

TIM_PACTL_PAEN = 1;
TIM_PACTL_PAMOD = 0;
TIM_PACTL_PEDGE = 1;
DDRT_DDRT7 = 0;

and I'm inputing a 1kHz square wave into PT7. but TIM_PACNT is always 0.

reading through the datasheet I think I read that I should add the code

TIM_TIOS_IOS7 = 1;
TIM_TCTL1_OM7 = 0;
TIM_TCTL1_OL7 = 0;
TIM_OC7M_OC7M7 = 0;

but I don't understand why. And it doesn't fix anything anyway.

Am I missing something? Thanks in advance.

Re: S12X Pulse Accumulator Troubles

kef — Tue, 03 Apr 2012 22:09:36 GMT

Port T pins are ECT pins, not TIM pins. S12XE has both TIM, and ECT timers, but connected to different ports.

Re: S12X Pulse Accumulator Troubles

jamienicol — Tue, 03 Apr 2012 22:47:58 GMT

So it's TIMIOC7 rather than IOC7, ie Port P not T.

Still, I updated the code and switched my input signal to the correct pin and still no luck. Any other ideas?

Re: S12X Pulse Accumulator Troubles

kef — Wed, 04 Apr 2012 01:20:09 GMT

By default TIM is routed to port R, not P. Use PTRRR to route TIM pins to port P.

Re: S12X Pulse Accumulator Troubles

jamienicol — Wed, 04 Apr 2012 16:34:07 GMT

Thank you! It works!