Digital input not detected

George Proost
Posts: 5
Joined: Thu Jan 22, 2015 11:44 am
Location: Turnhout, Belgium

Digital input not detected

Postby George Proost » Thu Jan 22, 2015 12:12 pm

Hello,

We're using your Unipi board, all is connected and configured as per your documentation.
In the photograph please see the test set up. On the Pi side of the optocoupler we expect to receive a high voltage at the on led. We get nothing. Please help if you can.
We can phone you if you give us your details.

Thanks.

unipi_digin_fault (Medium).jpg
unipi_digin_fault (Medium).jpg (118.58 KiB) Viewed 5738 times
tomas_hora
Site Admin
Posts: 298
Joined: Wed Oct 29, 2014 9:56 am

Re: Digital input not detected

Postby tomas_hora » Fri Jan 23, 2015 10:56 am

Hello,

have you enabled software pull-up resistors on the GPIOs? It needs to be done in order to make it work as described in this picture
GPIO-Input-Circuit2.gif
GPIO-Input-Circuit2.gif (7.47 KiB) Viewed 5723 times
George Proost
Posts: 5
Joined: Thu Jan 22, 2015 11:44 am
Location: Turnhout, Belgium

Re: Digital input not detected

Postby George Proost » Wed Jan 28, 2015 7:36 am

That did the trick.

Thanks!
chuckhinds
Posts: 8
Joined: Sat Jan 23, 2016 11:03 pm

Re: Digital input not detected

Postby chuckhinds » Thu Mar 10, 2016 7:33 am

Doesn't EVOK set the GPIO pull-up resistors for the digital inputs? I am testing the UniPi analog input with a pressure sensor using the "UniPi control panel" and it works perfectly. However the control panel says Input 7 is on, but nothing is connected to any of the digital inputs and the led on input 7 is not lit. I have tried rebooting, power cycling, and disconnecting the analog input, but it still says Input 7 is on. Any ideas?
tomas_hora
Site Admin
Posts: 298
Joined: Wed Oct 29, 2014 9:56 am

Re: Digital input not detected

Postby tomas_hora » Thu Mar 10, 2016 8:33 am

Did you make a clean installation of raspbian? Evok sets the pullup on startup but if there is another app using that gpio it may cause such troubles.
Second idea might be to check the cable between unipi and rpi if there are no shortcuts...
chuckhinds
Posts: 8
Joined: Sat Jan 23, 2016 11:03 pm

Re: Digital input not detected

Postby chuckhinds » Thu Mar 10, 2016 7:39 pm

You got it. I had a PiFace connected to this PI previously and didn't disable the SPI bus when I removed it. As you know, it's clock is on GPIO 11 (I07). I disabled the SPI, but it still didn't work. I found a forum on line that says you have to disable it twice before the GPIO pins it uses are freed up. Did it twice and now it works! Thanks for the help.
Attachments
GPIO Status.JPG
ESF_nl
Posts: 9
Joined: Mon Mar 14, 2016 3:11 pm

Re: Digital input not detected

Postby ESF_nl » Tue Mar 15, 2016 12:35 pm

Thank you! I was afraid my hardware was maybe broken http://unipi.technology/forum/viewtopic.php?f=14&t=216 but disabling SPI via

Code: Select all

sudo raspi-config
> advanced options
did the trick!
chuckhinds
Posts: 8
Joined: Sat Jan 23, 2016 11:03 pm

Re: Digital input not detected

Postby chuckhinds » Tue Mar 15, 2016 9:22 pm

Thought my hardware was broke too. Happy to have helped!

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