GPIO Module help...

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stevie232323
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Joined: Sun Feb 11, 2018 5:04 pm

GPIO Module help...

Post by stevie232323 » Thu Feb 22, 2018 4:21 pm

Hi lovely people.
Another question: I have my Riotboard GPIOs working on Linux Ubuntu. SYSFS is enabled. I can turn LEDs on and off using the terminal and the echo 1 > /sys/class/gpio etc etc commands...

Can someone please explain to me how the GPIO module works. I have seen the R-PI video but this is not an explanation. There isn't much in the docs...
I have tried setting the GPIO module output to on, have it connected from a drum synth on full volume and selected all the pins but no joy...
So please please some more help?? pleeeeeease?????
Thankyou again. xxxxxx
Steve.S

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NightRadio
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Re: GPIO Module help...

Post by NightRadio » Fri Feb 23, 2018 8:55 pm

Please show a complete list of commands that you use to turn on/off the LED

stevie232323
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Re: GPIO Module help...

Post by stevie232323 » Fri Feb 23, 2018 9:21 pm

OK. Heres an example of making pin 5 of the expansion port a GPIO output:
First I use Devmem2 to make the pin an output like so: "devmem2 0x20E009C w 0x05"
Then I make it available to the user (me) like so:

cd /sys/class/gpio

This command muxes the pin. Because I am using GPIO4_16 then I make the GPIO available by using the Linux naming convention for pins / peripherals:

GPIO4_IO16 maps to (4 - 1) * 32 + 16 = 112.

echo 112 > export

cd into its directory:
cd gpio112

Tell the pin its an output:
echo out > direction

and then tell it to either turn on or off:
And now, you can control state with :

echo 1 > value (high state, more or less 3.3V)

echo 0 > value (low state, more or less 0V)

Thats how I do it in terminal. Simple once you know how...
But why nothing from Sunvox?
I've tried using an amplifier module to boost the levels but still nothing..

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NightRadio
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Re: GPIO Module help...

Post by NightRadio » Mon Feb 26, 2018 3:01 pm

echo 112 > export
I think this is the reason. GPIO module can't write to pin 112, because the maximum value is 64.
I will increase it in 1.9.4

stevie232323
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Joined: Sun Feb 11, 2018 5:04 pm

Re: GPIO Module help...

Post by stevie232323 » Wed Feb 28, 2018 5:18 am

ohhhhhhh THANKYOU Nightradio.... я люблю тебя . x

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