Skip to content

Latest commit

 

History

History
54 lines (44 loc) · 2.9 KB

README.md

File metadata and controls

54 lines (44 loc) · 2.9 KB
Raw

Introduction

This is a fork of https://github.com/adafruit/Adafruit-Retrogame by having added code from https://github.com/dabonetn/C64USBKey/ to allow direct attachment of a C64 keyboard and up to two joysticks to your Raspberry Pi without the use of another controller.

Work in progress!

Details

As discussed in https://www.lemon64.com/forum/viewtopic.php?t=55650 and https://www.lemon64.com/forum/viewtopic.php?t=70692 a keyboard of a Commodore 64 home computer (and similar ones) consists of a wired matrix allowing the use of 8 outputs and 8 inputs. By adding two more inputs the matrix is extended from 80 to a hundred possible switches (keys, buttons and digital four-way-sticks) for the full keyboard and two Atari compatible joysticks. A second fire button would be possible, personally I'm not using it since the C64 makes no use of it.

schematics

Status

  • The wiring involves a male-to-male adapter on the side of the C64 keyboard connector. This ensures complete disassembly of this project to resume operation of the original hardware – if ever needed. In my case this adapter makes pins 1..20 connect all even numbered pins of a standard 40 pin flat cable – used in the years of IDE hard disk drives.
  • The Adafruit-Retrogame allows proper configuring. My yet trial project ist still hard coded. Moving stuff to the .cfg is in the plans.
  • Adafruit's is highly optimised to not load the CPU making use of interrupt triggered input reading. This sure no longer is possible whilst continuous strobing of outputs to have constantly updated input states. This makes this userland driver draining a Raspi 4 at almost 10% CPU load. - Any suggestions welcome.
  • Of course I will also need Adafruit's full consent to use their code in this project. However, I could not find any license information over at their site. I will simply ask before uploading any releases here.

wiring

To do

  • The driver does not yet provide support for the C64's power LED. This will come as soon as the power handling with some sort of onoff shim is done.
  • Since this project has its focus on the C64 and Vice emulator some configs need tweaking and adding to the repository.
  • As mentioned above the timing needs optimising as possible. Considerably Vice does delays of keyboard holded keys entirely by itself and joystick inputs need none of this. That being said the keyboard should be used in the console and other programmes as well. Hence a proper keyboard delay and repeat mode is to be implmented.
  • I'm really keen adding more key combos. Maybe making them configurable would be a thing.
  • Localisation for Vice is nothing since it handles the C64 rather natively. Back in the console interchanging the y and the z key relies on the keyboard driver people complained over at dabonetn's repository about it to an understandable extent.