AM3359: Reading eQEP index and strobe pin state

Nicolaj Jensen

Part Number: AM3359

I'm trying to find a way to read the current state of the eQEP index and strobe pins, without risking loosing a count latch.

Is there a way to see what the current state of these pins are without changing the pin muxing to be GPIO input, which means risk loosing the edge and thus the count latch.

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Hi,

What software are you using?

0 Nicolaj Jensen over 8 years ago in reply to Biser Gatchev-XID

Prodigy 60 points

I'm compiling using IAR EWARM.

My firmware is build to run on Micro Digitals smx rtos.

I fail to see the relevance of this as the question, at least in my mind relates to capabilities of the AM335x itself, not to any software.

Other processors allow one to read the pin state in the GPIO input register despite the pin being muxed to a peripheral. I believe the AM335x does not, so my question remains how can I get the current state of a eQEP pin when that pin is muxed to eQEP.

Best regards
Nicolaj

0 Biser Gatchev-XID over 8 years ago in reply to Nicolaj Jensen

TI__Guru**** 393215 points

OK, I see now what you need. Unfortunately in AM335x it's not possible to connect a pin to multiple internal peripherals. The only workaround for this is to feed the input signal to two pins - one eQEP input and one GPIO in parallel. The eQEP itself has only the capability to generate interrupts on Index and Strobe events.

0 Nicolaj Jensen over 8 years ago in reply to Biser Gatchev-XID

Prodigy 60 points

Thank you Biser

I was hoping I'd missed something.

I'd click "Verify Answer" on your post, but I'm not getting such a button, in it's place there's a reject answer

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AM3359: Reading eQEP index and strobe pin state