GPO_CFG setting in timer mode

Marlon Jose Masbad

Hi, there,

My question is when I set timer in timer mode (either one shot or auto reload), can I set TCLR CPO_CFG pin to 0 if I don't want to get any output pulse when overflow interrupt happen? Someone mentioned that once GPO_CFG is set to 0, timer will be in capture mode. Is that true?

Thanks

shen wei

over 12 years ago

0 Biser Gatchev-XID over 12 years ago

TI__Guru**** 393215 points

What processor is this?

0 Marlon Jose Masbad over 12 years ago in reply to Biser Gatchev-XID

Intellectual 740 points

Biser Gatchev-XID said:

What processor is this?

Am335x

0 Biser Gatchev-XID over 12 years ago in reply to Marlon Jose Masbad

TI__Guru**** 393215 points

I'm asking because I cannot find a pin with this name in the datasheet and TRM. Can you clarify?

0 Marlon Jose Masbad over 12 years ago in reply to Biser Gatchev-XID

Intellectual 740 points

It is in TCLR register bit 14. It control PORTIMERPWM and PIEVENTCAPT

0 Biser Gatchev-XID over 12 years ago in reply to Marlon Jose Masbad

TI__Guru**** 393215 points

OK, I understand now. Bit 14 in the TCLR register directly controls the PORGPOCFG, which is an internal signal. According to the AM335X TRM, Rev.H, Section 20.1.2.4 Timer Pin List:

"The timer PIEVENTCAPT input and PORTIMERPWM output signals are muxed onto a single TIMER I/O pad. The pad direction (and hence the pin function) are controlled from within the DMTimer module using the PORGPOCFG signal as an output enable."

So making GPO_CFG = 0 will effectively make the TIMERx pin a capture input.

0 Marlon Jose Masbad over 12 years ago in reply to Biser Gatchev-XID

Intellectual 740 points

Thanks, Biser.

0 Marlon Jose Masbad over 12 years ago in reply to Marlon Jose Masbad

Intellectual 740 points

further clarification needed from you, Biser.

In TCLR register, say I set GPO_CFG = 0, TCM = 0 (no capture), AR = 0. Will I receive overflow interrupt from timer or timer actually is running at Capture mode? Thanks.

0 Biser Gatchev-XID over 12 years ago in reply to Marlon Jose Masbad

TI__Guru**** 393215 points

I think the timer will overflow and not run in capture mode, but you can try and see what happens.

0 Marlon Jose Masbad over 12 years ago in reply to Biser Gatchev-XID

Intellectual 740 points

Thanks again.

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GPO_CFG setting in timer mode