P9_42 as a standard gpio pin

[gem...@gmail.com]

I would like to use pin P9_42 as a standard gpio pin to control a device. However, it seems I am getting a repeating 17 pulses over 4 seconds with a 1 second pause on P9-42. Using "config-pin -a P9.42 in" the pulses stop, but I cannot use this pin as gpio. As soon as I set it to out the pulses start up again.

gpio-7     (ECAP0_IN_PWM0_OUT   |P9_42               ) out lo

gpio-114 (MCASP0_ACLKR              |P9_92               ) in  lo

Not sure how to stop the pulses. Any ideas out there?

[Dennis Lee Bieber]

On Fri, 3 Aug 2018 07:55:00 -0700 (PDT),
gem...@gmail.com declaimed the following:

I don't recognize your listing there, but what (immediately after a reboot,
before any use of config-pin to set things) does

debian@beaglebone:~$ config-pin -q p9_42
P9_42 Mode: default Direction: in Value: 0
debian@beaglebone:~$
debian@beaglebone:~$ config-pin -a p9_42 out
debian@beaglebone:~$ config-pin -q p9_42
P9_42 Mode: gpio Direction: out Value: 0
debian@beaglebone:~$

display.

A stream of pulses makes one think something is overriding and running
the pin as PWM, SPI1 Clk, or UART3 TX.


--
Wulfraed Dennis Lee Bieber AF6VN
wlf...@ix.netcom.com HTTP://wlfraed.home.netcom.com/

[gem...@gmail.com]

This is the output at boot:

P9_42 Mode: default Direction: in Value: 0

# config-pin -a p9_42 out 

P9_42 Mode: gpio Direction: out Value: 0

[gem...@gmail.com]

The output is listing is from the PINS file.

On Friday, August 3, 2018 at 10:55:00 AM UTC-4, gem...@gmail.com wrote:

[Dennis Lee Bieber]

On Fri, 3 Aug 2018 11:00:36 -0700 (PDT),
gem...@gmail.com declaimed the following:

>This is the output at boot:
>
>P9_42 Mode: default Direction: in Value: 0
>
># config-pin -a p9_42 out
>P9_42 Mode: gpio Direction: out Value: 0
>

Well, nothing blatantly obvious there. I was hoping it might show
something different. The only other thing I'd investigate is to make sure
one does not have something running that might be doing things in the
background.

Sorry.

[gem...@gmail.com]

My thought as well - but not idea what from the normal OS.

On Friday, August 3, 2018 at 10:55:00 AM UTC-4, gem...@gmail.com wrote:

[TJF]

P9_42 (such as P9_41) is a double pin. It's connected to two CPU balls. The tool config-pins doen't handle that correctly.

Make sure that both CPU balls get proper configuration:

config-pin -a p9_92 in
config-pin -a p9_42 out  

Note: you can damage the CPU when both CPU balls are in output mode at different levels!