ZX Spectrum ROM Disassemblies

ROM Disassemblies were a very popular learning aid for home computers in the 1980’s. Usually they where in book form and most popular computers had at least one. The ZX Spectrum was very popular.

The Complete Spectrum ROM Disassembly book by Frank O’Hara and Ian Logan is the book I suspect many of familiar with, I know it was the first one I came across in my Spectrum days. It’s one of the best ROM listings I’ve read. Making it a great educational source for anyone interested in Z80 code.

Here’s the list:

The Complete Spectrum ROM Disassembly
https://worldofspectrum.net/item/2000076/
https://archive.org/details/CompleteSpectrumROMDisassemblyThe

Spectrum ROM Disassemblies
https://github.com/ZXSpectrumVault/rom-disassemblies

The Uncommented Spectrum ROM Assembly
https://github.com/cheveron/zxrom

Spectrum ROM disassembly
https://github.com/skoolkid/rom

Spectrum 128 ROM disassembly
http://www.fruitcake.plus.com/Sinclair/Spectrum128/ROMDisassembly/Spectrum128ROMDisassembly.htm

Timex Sinclair 2068 ROM disassembly
https://www.timexsinclair.com/computers/timex-sinclair-2068/technical/home-rom-disassembly/

If you know of any more please leave me a comment and I’ll add them to the list.

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ZX Spectrum (and Z80) Programming

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I remember programming the ZX Spectrum in the 1980’s, first using BASIC and coping programs from the program listings popular in the computer magazines of the time and then my own programs. Video games were a very popular theme for myself. I remember writing a Blackjack (21) card game, a copy of the VIC20 “City Bomber” and also some rather poor arcade game copies. Once I had the hang of BASIC I made some poor attempts at Z80 assembly. “Moon Patrol” was one arcade game I tried to replicate in Z80 assembly (I think I wrote it in a mix assembly and BASIC). Unfortunately none of my programs survived.

So thinking about my previous Z80 assembly programming attempts I’ve collected a list of ZX Spectrum and Z80 programming sites.

As always, if you know of any more please leave me a comment and I’ll add them to the list.

ZX_Spectrum_128k_programming_lesson1
https://github.com/andydansby/ZX_Spectrum_128k_programming_lesson1

z80-sample-program – puts some colored lines on the ZX Spectrum’s screen
https://github.com/maziac/z80-sample-program

Z80 Instruction Set
https://github.com/maziac/z80-instruction-set

DeZog – The Z80 Debugger
https://github.com/maziac/DeZog

Isometric Ray Casting, Ahoy!
https://github.com/TomHarte/Isometric-Ray-Cast

ZX Spectrum isometric engine development
https://github.com/aberrocampon/ZX-Spectrum-Isometric-Engine

Chargen Maker – character generator
https://github.com/mobluse/chargen-maker

zx-fonts
https://github.com/dinodork/zx-fonts

Arcade-8×8-Character-Set
https://github.com/neosquid/Arcade-8×8-Character-Set-for-ZX-Spectrum-Next

ZX Graphics Editor by DuefectuCorp
https://github.com/Duefectu/ZXGraphics

PixelWorld – font conversion
https://github.com/damieng/pixelworld

SpectNetIDE – ZX Spectrum IDE – VisualStudio
https://github.com/Dotneteer/spectnetide

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Commodore 64 / C64 Video Modifications and Enhancements

A short collection of links for Commodore 64 video modifications and enhancements

This is a very short list so I’m sure it’s far from being complete. If you know of any more please leave me a comment and I’ll add them to the list.

C64-RF-Modulator with S-Video Mod
https://github.com/pmandes/C64-RF-Modulator

C64 A/V cable – theory and practice
https://ilesj.wordpress.com/2012/03/30/c64-av-cable-theory-and-practice/

Commodore Multimedia Breakout
https://c64os.com/buyersguide/multimedia_breakout

Proper C64 S-Video
http://www.commodoreserver.com/BlogEntryView.asp?EID=F4B967500A894E10BE4A104C65DB541E

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Raspberry Pi PICO / RP2040 Retro & Vintage Home Computer Emulation

This post started as a quick collection of Raspberry Pi PICO / RP2040 retro and vintage computing emulation links but with the Pico / RP2040 versatility, computing power and ingenuity of its developers quickly grow to include retro inspired Pico/RP2040 based electronics such as emulating ROM cartridges and generating video displays.

I’m sure this list its far from being complete so if you know of any other Pico / RP2040 retro computer inspired projects leave me a comment and I’ll add them to the list.

• Home Computers

Armachat & PICOmputer fusion with Raspberry PICO
https://hackaday.io/project/179854-picomputer

PICO ZX Spectrum 128k
https://www.pcbway.com/project/shareproject/PICO_ZX_Spectrum_128k_06f49cd7.html

PICOmputer ZX – Pocket ZX Spectrum
https://hackaday.io/project/184965-picomputer-zx-pocket-zx-spectrum

pico-zxspectrum
https://github.com/fruit-bat/pico-zxspectrum

RPi Pico As A Sinclair ZX Spectrum
https://www.youtube.com/watch?v=fxpBeyrRMsY
https://github.com/BirchJD

PICOVIC – VIC-20
https://github.com/jfoucher/picovic

C64 Pico project – I made a tiny Commodore 64 with a Raspberry Pi Pico!
https://github.com/silvervest/c64pico
https://github.com/silvervest/MCUME/tree/c64pico
https://www.youtube.com/watch?v=hgLhGpbC6E4

Commodore 64 Raspberry Pi Pico emulator
https://www.raspberrypi.com/news/commodore-64-raspberry-pi-pico-emulator/

M.CU.M.E = Multi CompUter Machine Emulator
https://github.com/Jean-MarcHarvengt/MCUME
https://github.com/silvervest/MCUME
TeensyCEC
https://github.com/Jean-MarcHarvengt/TeensyCEC

RP6502
https://picocomputer.github.io/

picoRGD2HDMI
https://sites.google.com/view/lorentek-rgb2hdmi

Ted Fried’s MCL64 Is a Teensy 4.1-Powered Drop-In Upgrade for Your Commodore 64
https://www.hackster.io/news/ted-fried-s-mcl64-is-a-teensy-4-1-powered-drop-in-upgrade-for-your-commodore-64-6630915d888d
https://github.com/MicroCoreLabs/Projects/tree/master/MCL64

PZ1_Pico – PZ1-system based on 65C02, Raspberry Pi Pico and 512KiB SRAM.
https://github.com/NollKollTroll/PZ1_Pico

• Cartridges

ZXPicoIF2ROM
https://github.com/TomDDG/ZXPicoIF2ROM

Raspberry Pi Pico based ZX Spectrum ROM interface
https://www.derekfountain.org/zx_pico_rom.php
https://spectrumcomputing.co.uk/forums/viewtopic.php?p=111414

zx-spectrum-pico-rom
https://github.com/derekfountain/zx-spectrum-pico-rom

Dr.Beep ZX Spectrum-PC iface
https://oshwlab.com/rcalcagno/fuente-ts-2068_copy_copy

Raspberry Pi Pico Becomes Commodore 64 Cartridge
https://github.com/cknave/c64-pico-ram-interface
https://www.tomshardware.com/news/raspberry-pi-pico-powers-c64-cartridge

Videocart Pi
https://github.com/ZX-80/PicoVideocart

CPC_PICOROM
https://github.com/mattcallow/CPC_PICOROM

Getting ROM Dumps by Post
https://trochilidae.blogspot.com/2023/01/getting-rom-dumps-by-post.html

Postal Pico ROM Reader
https://github.com/blackjetrock/postal-pico-rom-reader

Konrad Beckmann’s PicoCart64 Is a Raspberry Pi Pico or RP2040 Stamp-Powered Nintendo 64 Flash Cart
https://www.hackster.io/news/konrad-beckmann-s-picocart64-is-a-raspberry-pi-pico-or-rp2040-stamp-powered-nintendo-64-flash-cart-a91607ec53a7

• Misc

Stream – Raspberry Pi Pico PIO coding for the N64 cart – N64 #6
https://www.youtube.com/watch?v=IKj1fv8ry7Q

Build Your Own Computer – Emulate RAM/ROM For A 6502 Using a Raspberry Pi Pico
https://www.youtube.com/watch?v=elrf1nM5nco

Raspberry Pi Pico ZX Spectrum Microdrive Hardware Emulator
https://www.pcbway.com/project/shareproject/Raspberry_Pi_Pico_ZX_Spectrum_Microdrive_Hardware_Emulator_37750e81.html
https://github.com/TomDDG/ZXPicoMD

RC2040 – Z80 CP/M 80 emulation of RC2014 using the RP2040 (PI PICO) processor.
https://github.com/ExtremeElectronics/RC2040

RunCPM_RPi_Pico
https://github.com/guidol70/RunCPM_RPi_Pico

Nueva placa ESP32-SBC-FabGL de Olimex compatible con ESPectrum
https://zxespectrum.speccy.org/

• PICO video

RP2040-PICO-PC
https://github.com/OLIMEX/RP2040-PICO-PC

PicoVGA
https://github.com/Panda381/PicoVGA

PicoTerm – VGA Terminal for RP2014
https://github.com/RC2014Z80/picoterm

Pico16VGA
https://github.com/Panda381/Pico16VGA

pico_atomvga
https://github.com/hoglet67/pico_atomvga

pico-vga-6bit-demo
https://github.com/moefh/pico-vga-6bit-demo

PicoElfTMS9118VIOCard
https://github.com/fourstix/PicoElfTMS9118VIOCard

PicoVideoModule (6847)
https://github.com/jimbro1000/PicoVideoModule

PicoMite-VGA-Edition
https://github.com/UKTailwind/PicoMite-VGA-Edition

pico-composite-PAL-colour
https://github.com/guruthree/pico-composite-PAL-colour

mac-se-video-converter
https://github.com/guruthree/mac-se-video-converter

pico-mposite
https://github.com/breakintoprogram/pico-mposite

https://github.com/obstruse/pico-composite8pico-composite8

Pico-VGA: A micro controller video card
https://github.com/benkyd/pico-vga

Bitbanged DVI on the RP2040 Microcontroller
https://github.com/Wren6991/PicoDVI

PicoDVI – Adafruit Fork for Arduino IDE + Adafruit_GFX compatibility
https://github.com/adafruit/PicoDVI/

PicoVGA – VGA/TV display on Raspberry Pico
https://github.com/Panda381/PicoVGA

VGA output for the Raspberry Pico in the Arduino IDE
https://github.com/Pancra85/VGA_graphics

PicoVGA with Joystick Build
https://hackaday.io/project/186747-picovga-with-joystick-build
https://land-boards.com/blwiki/index.php?title=PicoVGA01

Adafruit Feather RP2040 DVI PCB
https://github.com/adafruit/Adafruit-Feather-RP2040-DVI-PCB

Adafruit PiCowbell DVI Output for Pico – Works with HDMI Display PCB
https://github.com/adafruit/Adafruit-PiCowbell-DVI-Output

PicoDVI-1024×600
https://github.com/DRAgon734465502/PicoDVI-1024×600

Building an Interak-like VDU using the Raspberry Pi Pico – Part 1 & 2 & 3 & 4
https://www.evolutional.co.uk/post/interak-like-vdu-pt1/
https://www.evolutional.co.uk/post/interak-like-vdu-pt2/
https://www.evolutional.co.uk/post/interak-like-vdu-pt3/
https://www.evolutional.co.uk/post/interak-like-vdu-pt4/

ZX-Sprite Hardware Prototype – Part 1 & 2
https://www.evolutional.co.uk/post/zxsprite-hardware-prototype-pt1/
https://www.evolutional.co.uk/post/zxsprite-hardware-prototype-pt2/

A Heavy Overclock Pushes PAL-Standard Video From a Raspberry Pi RP2040’s PIO Blocks
https://www.hackster.io/news/a-heavy-overclock-pushes-pal-standard-video-from-a-raspberry-pi-rp2040-s-pio-blocks-ce895afd0d48

QLpicoVGA – Video Interface QL-to-VGA with a Pi Pico
https://github.com/holmatic/video_if_ql_vga

pico_atomvga Acorn Atom
https://github.com/hoglet67/pico_atomvga

RetroZX: propeller ZX Spectrum Clone
https://github.com/cbmeeks/RetroZX

ESP32
ESP32 S3 VGA
https://github.com/bitluni/ESP32-S3-VGA

Please check out my “8-bit Shack” retro computing channel

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Commodore C64 Test / Diagnostic wire harnesses

Testing a Commodore 64 can be made much easier if you have a set of test / diagnostic wire harnesses.

Retro Ninja 586220 C64 Diagnostic Harness
https://github.com/RetroNynjah/586220-C64-Diagnostic-Harness

The Commodore C64 Diagnostic Setup
https://ist.uwaterloo.ca/~schepers/diagnostic.html

C64-Diagnostic-Rev.-586220-Harness
https://github.com/svenpetersen1965/C64-Diagnostic-Rev.-586220-Harness

1541 Diagnostic Cartridge
http://blog.worldofjani.com/?p=2180

Cable Making
http://tech.guitarsite.de/cable_making.html
*
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Sinclair ZX Spectrum Software development tools (& reverse engineering)

Every since the very beginning Sinclair ZX Spectrum video games have been reverse engineered to give the gamer extra life, better game play or just fix software bugs that had creeped into games.
The computing magazines of the day would full of readers tips and provide lists of the vital poke addresses and values to make the changes.

And today, even over 40-years after in was released in 1982 the Speccy still has an amazing following.
As well as making new video games for the Speccy there is a lot of activity reverse old titles. Seeing what slick programming tricks the games programmers used to make their 8-bit wonders never gets old.

So here are a few sites I’ve found that I think are useful. If you know of any more please leave me a comment and I’ll add them.

Software development tools (& reverse engineering)

SkoolKit – SkoolKit is a collection of utilities that can be used to disassemble a Spectrum game
https://skoolkit.ca/
https://github.com/skoolkid/skoolkit

Spectrum Analyser – a tool (combination of an emulator, debugger and interactive disassembler) designed to help reverse engineer Spectrum games
https://colourclash.co.uk/spectrum-analyser/
https://github.com/dpt/8BitAnalysers

Spectrum Graphics Editor
https://retrospec.sgn.net/info.htm?id=sge&t=u

Examples:
Chase H.Q. disassembly project
https://www.davespace.co.uk/blog/20230524-chase-hq-disassembly.html

The complete Manic Miner disassembly
https://skoolkit.ca/disassemblies/manic_miner/

Please check out my “8-bit Shack” retro computing channel
and my Tindie store.

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Pong video game consoles and a little of their history

I picked up a couple of old Pong video game consoles recently and I was interested in finding out a little more about Pong. So here’s a few links I found interesting:

Pong on a chip
https://www.pong-story.com/gi.htm

Homebrew First-gen Console (AY-3-8500)
https://forums.nesdev.org/viewtopic.php?t=19701

An Interview With Duncan Harrower (“Pong-In-A-Chip” Inventor)
https://www.gamingalexandria.com/wp/2022/01/gilbert-interview/

Reverse Engineering the AY-3-8500, part 1: Demystifying the Pins
https://nerdstuffbycole.blogspot.com/2018/01/reverse-engineering-ay-3-8500-part-1.html

Pong TV game – A Scratch build Scale project
http://www.dragonslairfans.com/smfor/index.php?PHPSESSID=d3ded4822d60b7915bb3c00c24bdd9e5&topic=3613.0

Consoles and Competition
https://stratechery.com/2022/consoles-and-competition/

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Texas Instruments TI99/4A Clones

Based in the UK, the Texas Instrument TI99/4A is not a computer I had seen much of when it was introduced in the early late 1970’s and early 1980’s. It its purported to be the first 16-bit home computer and we would not see any 16-bit machines until the Commodore Amiga and Atari ST in the mid 80’s and maybe the Sinclair QL if you consider its cut-down MC68000, MC68008 a 16-bit machine internally.

So I found some technical websites that have some information on how to make you very own TI99/4A clone:

Texas Instruments TI99/4A Clone(ish) Project
https://github.com/danwerner21/TI99_22

Texas Instruments TI99/4A Motherboard Replacement Project
https://github.com/danwerner21/TI99-Motherboard

Texas Instruments TI99/4A Motherboard Replacement Project
https://github.com/rkrenicki/TI99-Motherboard

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Commodore 64 and VIC-20 3D printed replacement parts

I was looking to replace a lost C64 connector plate and found a few DIY options to choose from. So here’s a short-ish list of 3D printed replacement plastic parts:

Commodore 64 connector plate
https://www.thingiverse.com/thing:959633
https://www.thingiverse.com/thing:4376815
https://www.thingiverse.com/thing:3761804
https://www.thingiverse.com/thing:3791063
https://www.thingiverse.com/thing:3753156

Commodore 64 PSU power supply case (new)
https://www.thingiverse.com/thing:3126844
https://www.thingiverse.com/thing:3574072
https://www.thingiverse.com/thing:5656941

Commodore 64 PSU power supply case (old VIC20 style)
https://www.thingiverse.com/thing:3761669

Commodore 1541 Disk Drive
https://www.thingiverse.com/thing:4544524

Commodore 64 label
https://www.thingiverse.com/thing:4218692

Commodore 64 Model
https://www.thingiverse.com/thing:5384117

Commodore 128 Model
https://www.thingiverse.com/thing:5404370

Commodore 64GS replica
https://www.thingiverse.com/thing:5623120

Commodore VIC20

Commodore VIC-20 VC 20 connector plate
https://www.thingiverse.com/thing:3886556

Commodore Vic 20 Rainbow label
https://www.thingiverse.com/thing:4218696

Commodore VIC-20 power adapter
https://www.thingiverse.com/thing:5443160

Other Commodore computers

Commodore PET Replacement Keyboard
https://www.thingiverse.com/thing:4585902

PSU adapter for TRACO TOP 60252 in Commodore CD32 PSU
https://www.thingiverse.com/thing:5956840

Please check out my “8-bit Shack” retro computing channel

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Composite Video lead build for Dragon 32

From my “8-bit Shack” retro computing channel

Composite Video lead build for Dragon 32
https://www.youtube.com/watch?v=PmbEFJPBqeU

Building a Composite Video lead for a Dragon 32 from a 35-year old loft find.

Dragon 32 (from Wikipedia):
https://en.wikipedia.org/wiki/Dragon_32/64

Dragon 32 Pin-out for Video Monitor 5-pin DIN:
http://dragon32.info/info/pinouts.html

RCA Connector details:
https://en.wikipedia.org/wiki/RCA_connector

Mini-DIN Connector details:
https://en.wikipedia.org/wiki/Mini-DIN_connector
https://en.wikipedia.org/wiki/DIN_connector

Dragon Logo redrawn by Thomas Gutmeier from:
http://www.8bit-homecomputermuseum.at/downloads/downloads.html

http://dragon32.info/info/pinouts.html
https://en.wikipedia.org/wiki/Shielded_cable
https://en.wikipedia.org/wiki/Speaker_wire
https://en.wikipedia.org/wiki/Copper_conductor
https://en.wikipedia.org/wiki/Wire

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https://www.youtube.com/@8bit-shack

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