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Question

gpio157 not accessible

posted in IGEPv2
Saturday, April 26 2014, 11:11 PM
peter
peter
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0
Good Morning

I am trying to use 10 gpio's with direction = "out" for an HD44780 character display attached to J990 of my igepv2.
Specifically gpios: 136,137,138,139,156,157,158,161,162.

All work in a blink-led test except gpio157. It has been set up by the kernel as an "in" pin and I cannot change it.

In bash, I get:

sh-4.2# echo 157 > /sys/class/gpio/export
sh: echo: write error: Device or resource busy

sh-4.2# echo 157 > /sys/class/gpio/unexport
sh: echo: write error: Invalid argument

sh-4.2# echo 0 > /sys/class/gpio/gpio157/value
sh: echo: write error: Operation not permitted

sh-4.2# cat /sys/class/gpio/gpio157/value
In my program (which is very similar to examplebeta1) I get "open" errors for all gpio's but it still works - except for gpio157. I can see the ISEE default allocation of gpio's from

cat /sys/kernel/debug/gpio

GPIOs 128-159, gpio:
gpio-136 (MCP251X NRESET ) out hi
gpio-137 (BT NRESET ) out lo
gpio-138 (WIFI NPD ) out lo
gpio-139 (WIFI NRESET ) out lo
gpio-157 (MCP251X IRQ ) in hi




My question#1 is: Is there a way to unexport gpio157 and/or change the direction to "out"?
My question#2 is: I need 6 more gpio pins from J990 for another device. I need to keep my SD card working (nothing else). Suggestions on which pins/modes and how can I change modes?

Thanks in advance

Peter

Accepted Answer

peter
peter
Offline
Monday, April 28 2014, 07:54 PM - #permalink
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I commented out buddy=igep0022 in igep.ini and gpio157 now works.
Thanks eballetbo!!

Peter
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Responses (2)
  • Accepted Answer

    Monday, April 28 2014, 11:14 AM - #permalink
    0
    Hi Peter,

    Check if in your igep.ini there is the following line:

    buddy=igep0022

    If is there, please remove it. As you don't use the IGEPv2 EXPANSION BOARD this line is not required. The pin 157 is configured for this expansion board.

    Hope it helps
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  • Accepted Answer

    Thursday, August 16 2018, 09:20 PM - #permalink
    0
    That is all done to keep the software under control and to keep it more secure from the hackers because there are everyday more and more hacking softwares are coming in the market which can crack any software like ukbestessays review so we need to protect ours.
    The reply is currently minimized Show
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