Bela Gem Stereo digital I/O help!

JuicyJr

Hi everyone,

I’m currently working on a custom Modal Synthesizer project running on a Bela Gem Stereo using puredata. I’ve run into a bit of a wall trying to get digital inputs working within a Pure Data patch.

to give you context, this is the circuit im using for the hardware :
Circuit: A simple digital button in a breadboard which is wired correctly to the bela using a jumper cable and a resistor, and the button receives the GND of the bela too.
I have it connected to the pin labeled Digital 0 ( which the hardware identifies as D0, P1.21).

The Problem:
I am testing this in a clean Pd patch, but I can't seem to get a signal. I’ve tried the following logic based on the standard Bela examples:

Sent a [loadbang] to a [in 11( message connected to [ s bela_setDigital].

Attempted to read the signal using [r bela_digitalIn11] connected to a [print] object expecting the values get sent to the IDE console.

I noticed a discrepancy in the documentation/examples:
Most example projects refer to the digital input as the pin number 11, but the hardware seem to identify it as pin 21.

I tried changing the Pd message to [in 21( and reading from [r bela_digitalIn21] to match the physical header number, but still no luck. The hardware is powered, the wiring appears correct, and the rest of the Stereo Gem is functioning perfectly.

My Questions:

On the Bela Gem Stereo, what is the correct way to initialize Digital 0 as digital input?
Are there any additional steps required to initialize the digital pins on the Stereo Gem compared to the original Bela?
i just want to know how the bela gem stereo identifies the hardware digital pins and how a puredata project is able to read them.
sorry for my english, any guidance is appreciated! : )

giuliomoro

The method you describe should work (though it's no longer the recommended one). I am wondering whether it's a wiring issue.

First off make sure your board is up to date: use the update button in the IDE and go through the process.

Look at the pure data language-overview example on the board, it shows how to do this using the abstraction [bela/digital-in] which simplifies things. You can install the abstractions via deken (PureData's built in extension manager) or simply downloading them from here: https://github.com/BelaPlatform/bela-pd-abstractions.

Now for the wiring. With the program running click the bottom icon on the sidebar to open the hardware tab. While the program is running you can monitor the state of the digital pins. Make sure digital channel 0 displays a "IN" and that the color changes from light blue to dark blue when you press it. If it doesn't, check your wiring.

JuicyJr

giuliomoro perfect! the problem was solved, thank you so much! : )

giuliomoro

Was it a wiring or code issue?

JuicyJr

giuliomoro actually it was both... i connected the digital buttons the wrong way and on top of that i had to use the abstraction for the digital inputs to communicate inside the bela project.