Is it possible to use normal tactile buttons as controllers?

[Tam-vir]

Hey there! I found your project interesting so I built the emulator on my raspberry pi pico. I didn't have any have any idea about ZX spectrum until just now, I thought I could use tactile buttons as controller. But then I saw it wasn't working. So I searched about ZX spectrum and realized I had to order PCB for that. But I'm somewhere in the world where custom PCBs are rarely produced and costs a lot. So, is it possible to make tactile buttons on breadboard work too?

Thanks a lot for reading :)

[antirez]

Helo @Tam-vir, yes I believe you can definitely do this. If you check the configuration file of the device, you can define not just the pin, but also the "getter" function that will report the Pin status. This means that writing some wrapper code, you can also connect i2c joypads or alike. Moreover I'm near to release a version that uses a lot less RAM and is definitely faster. With the empty RAM on the Pico it will be possible to have more space for custom code. Btw I have never used tactile buttons, but I believe that most of the times they already output +5v when touched or something like that, so you can basically handle them as normal buttons. Probably not even code changes are needed but it depends on the exact buttons and how they work.

[Tam-vir]

@antirez Actually, by tactile buttons, I mean the usual switch. Like the ones we use to turn on/off lights. You can connect any GPIO pins and a GND pin and use that current flowed from GND to that Pin as an input (like 1/0 or On/Off or Pressed/Not Pressed). 0-0.8V is considered 'Off' and 2.2V to 3.3V is considered 'On'. That's why we can use between that gnd pin and a gpio pin as a controller button.

You could try reading this: https://deepbluembedded.com/raspberry-pi-pico-w-digital-inputs-outputs-c-sdk-rp2040/

Tbh I usually code my pico in python and I just have the basic knowledge in C/C++. That's why I was planning to modify the code but couldn't do it. So I was wondering if you could make an edition that supports gpio pins as inputs to use it with push/tactile buttons. That could make this project even more easier to use and make it available to even more people to try!

Thanks again! :)

[marvbloke]

You can connect your tactile buttons to any GPIO pins and define them in the 'device_config.h' file. The process is explained here: https://github.com/antirez/zx2040/tree/main/devices

If you're using the Tufty2040 pre-built UF2 file, the pins are defined as

// Pimoroni Tufty 2040 keys pins.
#define KEY_LEFT 7
#define KEY_RIGHT 8
#define KEY_FIRE 9
#define KEY_UP 22
#define KEY_DOWN 6