Brain surgery! RP2040 style (32u4 ft Raspberry pi Pico)

That’s a Pi Pico
Partying like it’s nineteen QWERTY nine!!

The interest in the mini keyboard is strong as ever, but – there’s a new kid on the block soon – The Amiga A500 Mini

That Beastie –

To turn this Mini’s ridiculously small keyboard into a ‘toothpicks required to operate’ WORKING keyboard will be tricky as it has a significantly larger number of keys than the C64Mini

Infact, there’s 96 on European Keyboards and 94 on others? ..Either way – it’s More than 81 – which is the maximum you can put on 9×9 Matrix – which exceeds the capacity of the good old 32U4 when used as a keyboard (well, technically, the Pro Micro I use has 20 GPIO available, Allowing for 100 keys IF I go and hack out the two LED’s and solder a bridge)

So…Enter the Fantastic (and new) Ruby Firmware for Keyboards – PRK,

Which can be found here –

https://github.com/picoruby/prk_firmware

and, with a good overview – here on Youtube (in Japanese, but, enable Captions and translate to English, you’ll get the gist of it)

It’s taken me a Solid Month to figure out how to get this far – I’m a relative noob to Linux, cross compilation, Ruby, C, and, generally ‘stuff’ like this –

To be able to compile this, i’ve setup WSL for Windows – which is essentially Ubuntu Linux, running nativley in Windows!

Inception! WSL running Ubuntu whilst i type this blog!

I’ve also had to setup the Raspberry Pi Pico-SDK

Ruby – For Linux – something higher than 2.6

Bundles for Ruby

And a few other things….all of which are quite finickitey and throw a wobbly at the slightest provocation! – Linux is fun eh!..

I’ll eventually get around to step-by step documenting and linking each step to ensure a good build environment so that others can duplicate what I’m doing

Once it’s all compiled, I drag the .uf2 file over to the pico (after holding bootsel whilst plugging it in) the thing reboots and becomes a keyboard

What’s Next………..

  • Ensure the Keymap is correct
  • Finish the basic keyboard layout, testing all basic keys
  • Introduce shifted keys
  • introduce ‘layers’ to ensure special keys are correct
  • introduce fancy stuff

Where this is going……………..The RP2040 Chip is fairly priced against the 32u4. I’m hoping that I can eventually switch the C64mini keyboard over to a fully SMT ready assembled kit – just add keycaps. And, i’m hoping I can do that for the Amiga Mini!, as much as I love soldering 600+ points, I appreciate some of you out there don’t!

And, I’ve another TOP SECRET project on the go also…It’ll blow yer mind! but, in 2022 that one, it’s a long burn that ‘looks’ finished (i’m holding it in my hands now!, all 2 circuit boards and about 100 3D printed pieces) but, needs quite a bit of work behind the scenes.

Also, Blinkenator, slow going, but I’m really trying, it’s just hard getting over this hurdle where it must be soldered….one last thing to try!

And, final before I go to bed, the C64 mini running the keybaord upgrade kit with pi Pico transplanted brains!

It’s being captured via a HDMI capture dongle and OBS studio so I can use my laptop as a test monitor!

Author: Bleugh

Early Fourties, Wife, two kids in primary school. Both of us work full time...5 years now we’ve been Back in Blighty after a decade away...It's a new country for everyone! Still finding time to tinker!

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