Here are some interesting resources if you want to code in assembler on Apple II.
This is absolutely not a complete list, your favorite search engine should give you a lot of results, but those are the websites that helped me the most.
Also, for generic 6502 algorithms, have a look at what the C64 scene can offer you!
Update 14/11/2022: added Dithertron, HackzApple, Burtal Deluxe, AccurApple
Update 18/10/2020: added Beneath Apple DOS and Apple ProDOS 2020, AppleWin FT edition, Social category
Update 16/07/2020: added 6502/65C02 opcode matrix, added Video 7 US patent
- Apple II Infinitum – (Slack) The biggest international community
- Apple II Touch – (Discord) French community
- Apple II French Underground – (Twitter) French cracktros
Generic 6502 and 65C02 reference
- 6502.org Tutorials – The reference site for 6502 and 65C02 CPUs
- 6502/65C02 opcode matrix – Useful sheet of all opcodes with timings
- Codebase64: 6502/6510 maths – One of many C64 resources for 6502
- The NMOS 65xx/85xx Instruction Set – With precise internal timings
- Visual Studio Code – C64 extensions add support for 6502 syntax coloring
- acme cross-assembler – 6502 cross-compiler, used by French Touch
- Merlin 32 by Brutal Deluxe – The reference 6502/65C816 cross-compiler for Apple II
- cc65 cross-assembler – 6502 cross-development full package
- AppleWin FrenchTouch edition – With extended debugger
- AccurApple – Cycle accurate Apple II emulator written in Rust, working on any OS
- AppleCommander – A2 disk image utility (creation/modification)
- GrafX2 – Paint tool (Win/Mac/Linux), v2.6 supports RGB HGR and DHGR
- ADTPro – PC/Mac <-> A2 fast disk transfer tool through a null modem cable
- Bmp2DHR – BMP <-> DHGR/DLGR converter for NTSC Apple II
- Dithertron – Image converter for a lot of 8/16 bits computers including Apple II
- WUSDN IDE – Eclipse 6502 plugin that integrates compilers, emulators and disk tools
- Apple II documentation project – Amazing archive of A2 tech reference: check index.txt!
- Understanding the Apple IIe – By Jim Sather, exhaustive analysis of the Apple IIe internals, a must read
- Beneath Apple DOS and Apple ProDOS 2020 – Revised edition of those two absolute reference books
- Revisiting Apple ][ hires – HGR mode fully explained with code tips
- Apple II graphics – Good overview of A2’s GR/HGR modes
- John Relay’s Apple II Archive – I/O Memory – Cheat sheet for A2’s hardware switches
- Apple II Double Hi-Res from the ground up – How to program DHGR
- DHGR – Pushing limits – Very complete writing on the mess that is NTSC DHGR
- Apple Underground (Archive) (French) – Lot of information on Le Chat Mauve RGB cards, DHGR mixed-mode used in Extasie and differences between NTSC and PAL A2
- HackzApple (French) – Lots of data on Apple II models, cards and software
- Apple II 64k cycle counting megademo – Amazing demo for Apple II+ by VMW prod
- Prince of Persia Code review – A great introduction to Apple II architecture
- Le Chat Mauve sur Apple II – (French) – List of all extended video modes of Le Chat Mauve RGB cards
- Video 7 RGB US Patent – Describes the RGB DHGR mixed mode, the 160×192 mode and how to implement them. Mixed DHGR was also used in Apple RGB and Le Chat Mauve « Féline ».
- French Touch Vault – All demos by French Touch with source code
- Latecomer – My first Apple II demo
- festro – Festro by Digarok
- dos33fsprogs – Disk tools, and the Apple II demos by VMW prod
- fdraw – Fast Apple II hi-res graphics by Andy McFadden
- Apple II PT3 Vortex Tracker Player – Vortex YM player by VMW prod
- a2-4am – Disk preservation and modern crack tools, .woz format
- Ctrl-Pomme-Reset – French Touch’s initial code archive from 2017, contains unreleased prods
- Prince of Persia Apple II – The official Prince of Persia source code by Jordan Mechner
Modern hardware upgrades for Apple II
- VidHD – Call-A.P.P.L.E.’s incredible HDMI card for Apple II
- Floppy Emu – BMOW’s floppy disk emulator for Apple II / Lisa / Mac. Can also act as a ProDOS hard drive if your Apple II has a smartport firmware.
- ROM 4X and 5X – Enhanced ROMs for the Apple IIc and IIc+
- a2heaven – Many upgrades, you can get the Mega audio soundcard there (emulates every audio soundcard available for the A2).
- Apple2.net – Ian Kim’s website, home to the Mockingboard 4c for Apple IIc. He sells it on eBay when a batch is available.
- How to fix Apple Joystick’s buttons – Instead of buying another one 🙂
- Open Source Scan Converter – Converts analog RGB to HDMI, it works very well with Le Chat Mauve RGB cards and adapters.