AR150 schematic

Is there a schematic available?

I like to know if there are pull up or pull down resistors attached to the gpio 7 and 8 toggle switch and where they are located, and if there are other components attached.

unfortunately, AR150 is not open hardware. But if you specific your question, we can try to answer.

I want to use the GPIO 7 and 8 and i just need t know if there is a pull up or pull down being used.
Where they sit on the PCB in case i need to remove them
What other components are attached to these GPIO’s (that may, or may not interact with my hack) capacitors or diodes?

Ideally I need clean gpio 7 and 8 connections a VCC and a GND.

A partial schema is that an option? Of GPIO’s pull up pulldown placement and how the traces run. And eventually also the DC/DC converter to be able to verify eventual mistakes more easy.
I know… what i ask is already 50% of the schematic, I just hope to make things more understandable / more inviting to beginning hardware hackers.

Both of GPIO7 and GPIO8 have a pull down resistor by default,they are R17(GPIO7) and R19(GPIO8),you can see them beside the switch.And nothing else is attached on the GPIO’s.

So r21 is not involved? Or is r21 a 0 ohm to VCC?

R21 is a 10K resistor to 3.3V . When you switch the switch to one side the R21 is involved.It gives a pull up to the GPIO7/8 . So that we can distinguish the action of switching the switch.

Yea understood, I’m about to hook up a rotary encoder

Typically they use pull ups and debouncing caps
rotary encoder sch

I’m trying to make a modification thats easy for beginners with minimal soldering skills. So i’m taking my time to look at this. With R17 and R19 being pull downs my initial idea becomes a bit more complicated. And might need more advanced soldering skills. :slight_smile:

I could hook it up in reverse but that would only cause confusion to beginners.

At this point the best option seems to remove the switch, R17 and R19. And then hook it up the regular way.
Using a rotary encoder for prototyping that has the resistors and capacitors in place.

Another option would be to do the debouncing in software. And just use a plain encoder.

I don’t have any hardware elektronics knowledge, but how about using the GPIO pins 1, 14, 16 and 17 near the UART pins? Header pins doesn’t cost much and I think it should be do-able to solder it.

Yes thats also an option, though I want to make use of as many GPIO’s as possible.

But yea, I could use 16, 17, 3v3 and GND for now. In fact I will do that. Thanks for the suggestion.
Still… for my own project I will hack the mode switch.

Another gpio related question: is gpio23 connected anywhere? Is there any way to use it? Thanks.

Sorry no gpio23 exposed

Gpio23 is also SPDIF out on the controller.

If you ever happen to redesign the PCB, imho it would be considerable to make this pin available as this pin solely would allow digital audio usage.