2 layers178.4 × 115.6 mm
CR2021 CPU v2
derpflanz/castle-runner
This is my hobby project in making a 6502 based 8-bit computer from scratch. The end goal is to have it run Castle Runner, a game I made many moons ago.
47 parts
2 layers57.2 × 73.7 mm
Programmer
derpflanz/castle-runnerThis is my hobby project in making a 6502 based 8-bit computer from scratch. The end goal is to have it run Castle Runner, a game I made many moons ago.
- Size
- 57.2 × 73.7 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 3
- Nets
- 38
- Pads
- 78
- Tracks, vias
- 247, 10
- Routed
- Yes
- KiCad
- KiCad 5 (file 20171130)
- Created
- 31 Jan 2021
- Updated
- 24 Aug 2026
Overview
Programmer is an open-source printed circuit board by derpflanz, from the derpflanz/castle-runner repository on GitHub. It is a 2-layer board of 57.2 × 73.7 mm with 3 parts on 38 nets, routed with 247 tracks and 10 vias.
It is built around the 74LS273PC. It belongs with the interfaces and adapters boards and the AVR (ATmega, ATtiny) boards of this library.
Main components
1README
README.mdcastle-runner
This is my hobby project in making a 6502 based 8-bit computer from scratch. The end goal is to have it run Castle Runner, a game I made many moons ago.
CR Assembler
Castle Runner is built from scratch, including the assembler (new version, written in C). I created my own assembly language dialect to assemble the machine language code. That ML can then be written to a EEPROM. For which I built my own EEPROM programmer.
Layout
By default, the RESET vector is set to $8000, which is the start of the ROM in the CR001 computer. The VirtualCR001 uses that as well by default. When programming the EEPROM, this vector is sent as the first two bytes and stored in $FFFC/$FFFD in the ROM.
Note that the assembler can have a DATA section at the start, which will cause to use another RESET vector to be written at the start of the .hex file.
Parts
3| Qty | Value | Footprint | References |
|---|---|---|---|
| 1 | 74LS273 | Package_DIP:DIP-20_W7.62mm | U1 |
| 1 | Arduino_Nano_v3.x | Module:Arduino_Nano | A1 |
| 1 | KM62256CLP | Package_DIP:DIP-28_W15.24mm | U2 |
Questions
How big is the Programmer PCB?
It measures 57.2 × 73.7 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Programmer use?
3 parts, built around the 74LS273PC. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Programmer KiCad files?
From the derpflanz/castle-runner repository on GitHub, at the commit this page was made from: the board is Firmware/EepromProgrammer/schematics/programmer.kicad_pcb and its schematic ComputerDesigns/CR2021_CPU_v2/6522.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Programmer design in my own project?
Its repository states no licence, so its author keeps all rights: ask derpflanz before reusing the design.
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