GPIO wiring

[pucho812]

Can anyone explain GPIO wiring like I am a 2 year old.
From my understanding
Each in or out, there is an A or B, some times called hi (A) and lo (B) depending on desk. Hi side usually gets the voltage, lo side goes to ground. Can stick a switch between either side to get the Gpio to trigger.
Am I missing something here?
For example 12v source going through a spst switch connected to A/hi. Then I can tie B/lo to 0v. When engaging the switch it would trigger the gpio.

 

[Chrisfromthepast]

Thats how it works for the desks I’ve encountered.
This doc is about as muddy as any Digico literature:
https://digico.biz/wp-content/uploads/2020/02/TB112-SD-GPIO-Pin-Out.pdf
GPI’s have a pullup resistor on the high side and the low side is ground. I don’t think it always matters which ground pin.
The GPO’s are generally current limited.

 

[pucho812]

Here is what the manual has for GPIO.
They are kind enough to have it on a db25 and provide the voltage.
From there you can program in the digital desk what it does.
So as mentioned above I have my spst switch between pin 7(12vdc) and pin 1( input 1A)
And I have pin 14( input 1B) going to pin 20 ((0v).
Should be good correct?

 

[Chrisfromthepast]

For input, I would try simply shorting a GPI pair together with your switch, and see if that is sufficient.
Like take a jumper between pin 1 and 14 and see if that triggers it.
If so, just wire those pins to your switch and you’re done.

Usually the high side is pulled up to V+ through a pullup resistor like 5k ish, so you don’t really need the 12v source for your arrangement. Might even cause damage.
Is there another page in the manual that describes the GPIO or just this table?

 

[pucho812]

For input, I would try simply shorting a GPI pair together with your switch, and see if that is sufficient.
Like take a jumper between pin 1 and 14 and see if that triggers it.
If so, just wire those pins to your switch and you’re done.

Usually the high side is pulled up to V+ through a pullup resistor like 5k ish, so you don’t really need the 12v source for your arrangement. Might even cause damage.
Is there another page in the manual that describes the GPIO or just this table?

Another table from a different manual. Same manufacture. Same gpio pinout.

 

[Chrisfromthepast]

You had it right at first.
Do you have a switch that is momentary?
If so, the current limiting inherent in the gpi is probably plenty. If the switch is latching, pay attention to the current, and consider a small value resistor inline with the switch.

 

[pucho812]

Thank you for that picture.
It’s wired like that. But now I need to figure out why it does not trigger

 

[Chrisfromthepast]

Man, Im wrong alot. Do you have your scope and a load resistor? Im curious about that 10ma spec.
If you hold it a long time?
Do you have a 12v wall wart you can shock it with? I assume they designed 450ma 12V source to be perfect for this application with just a momentary foot switch.

 

[pucho812]

Success . Thank you for confirmation.
As originally wired which is the same as your drawing, I have it working.
At first I was concerned as I didn’t hear any relays.
But after a quick programming of the desk, my test set up worked.
I have a momentary switch hooked up. When I press it, boom/ on go my mute group. When I press it again off go my mute group.

 

[Chrisfromthepast]

BOOM
Stoked

 

[pucho812]

BOOM
Stoked

Thanks for the assistance