AM571x: PRU GPI reads

Gunter Schmer

Hi,

We are currently running PRU firmware to read GPI pins on PRUSS2 and reading the state of GPI pins with R31 reads. It turns out that if the firmware runs on PRU0 core, the GPI reads succeed, but if we read GPI pins with PRU1, then it fails with always getting "1".

For PRU0 we are reading specifically pr2_pru0_gpi2 on pin F9.

I need to check what pr2_pru1_gpiX we are exactly using.

But in the meantime if you could let me know if there is anything specific about gpi pins on pru1, that would be great.

Regards,

--Gunter

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

I will forward this to the PRU experts.

0 Jason Reeder over 9 years ago

TI__Genius 10440 points

Gunter,

To my knowledge there is nothing known about PRU1 on PRUSS2 that would cause this. I am checking with Melissa to verify.

Let us know which PRU1 pin you are accessing and which board you are using and we'll look at it further.

Jason Reeder

0 melissaw over 9 years ago in reply to Jason Reeder

TI__Genius 15900 points

Gunter,

Jason is correct. There is nothing unique with PRUSS2 PRU1 that would cause this.

To confirm, I just did a quick test by tying the following AM571x signals together, and I was able to see the PRUSS2 core1 GPI signals correctly reflect the value of the connected GPO signals.

PR2_PRU0_GPO12 --> PR2_PRU1_GPI5
PR2_PRU0_GPO13 --> PR2_PRU1_GPI6

Is there anything on the board that could cause contention? I'd also suggest checking the pinmuxing for the signals.

Regards,

Melissa

0 John Lusby over 9 years ago in reply to melissaw

Prodigy 130 points

Hi Melissa,

Would you be able to send me the source for that example test you did?

-John

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AM571x: PRU GPI reads