abn6502/README.md

# 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:

<a href="http://www.youtube.com/watch?feature=player_embedded&v=w5cA64xof2I" target="_blank">
 <img src="http://img.youtube.com/vi/w5cA64xof2I/mqdefault.jpg" alt="Watch the video" width="240px" height="auto" border="10" />
</a>

Video about the wireless bootloader:

<a href="http://www.youtube.com/watch?feature=player_embedded&v=NABU7gQDtcs" target="_blank">
 <img src="http://img.youtube.com/vi/NABU7gQDtcs/mqdefault.jpg" alt="Watch the video" width="240px" height="auto" border="10" />
</a>

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:

1) Send gerber files from /hardware to your favorite board house
2) Build the project using assemble.sh - 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.
3) 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.
4) Burn the ROMs. I use a TL866II Plus variant for the actual ROMs.
5) Solder away
6) 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.
7) 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/