2.8 KiB
Executable File
ABNielsen.com 6502 Single Board Computer R1
This is a 6502-based complete single board computer intended to help during the global IC shortage. Why use new chips when you can reuse scrap?
Complete hardware overview of R1:
Video about the wireless bootloader:
Check out the NEW project on HackADay if you want to read more and see some pretty pictures :)
https://hackaday.io/project/184725-abn6502-sbc-r1
For R1 I got rid of the Padauk MCU without increasing the chip count!
Build instructions:
- Send gerber files from /hardware to your favorite board house
- Build the firmware using assemble.sh (macOS/Linux) - this will also try to burn the main ROM using Minipro. Dependencies: [CC65] (https://github.com/cc65/cc65) and a way to burn the ROM's.
- Source the IC's - the spirit of this project is to contribute as little as possible to the global IC shortage and get used chips locally or from Ebay/AliExpress/etc.
- Burn the ROMs. I use a TL866II Plus variant for the actual ROMs.
- Solder away. If you can solder 0805 components(poorly), you should be fine. Some optional components (the microUSB connector, the 3v3 regulator, and the RF-module) require a bit more skill.
- For the PS/2-keyboard I use the 6522's Shift Register, PB6, and a 74xx74 flip flop. See my R1 Hardware overview at 7:46: https://youtu.be/w5cA64xof2I?t=466 This is now included on the board - instead of a PS/2 connector which can be harder to source I went with a USB-A-connector. Keyboard plugs straight into the board.
- Enjoy!
Optional: Setup SSH keys with a Raspberry Pi, connect an nRF24L01+ compatible module to it and compile the wireless bootloader code in /software_linux
Also optional: Microsoft BASIC can be enabled by cloning the msbasic Github repo into the same folder you cloned this repo.
git clone https://github.com/mist64/msbasic.git
Then uncomment ;BASIC := 1 (Remove the ";") and run assemble.sh - this will let you run BASIC by pressing F4. To change settings for BASIC, values can be changed in defines_abn6502.s
Also, please note that the current code assumes VRAM starts at $0800 rather than the default $2000 in the schematic - resistors will have pads for configuring in the next build, but for now it requires jumpers.
License: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) https://creativecommons.org/licenses/by-nc/4.0/