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Reference cards

Fourteen sheets, sized for letter paper, meant to be printed and kept next to the keyboard. Every one of them condenses a chapter — nothing is on a card that is not also somewhere in this guide, so a card is a shortcut, never the only copy.

They open as plain pages outside the guide. Use your browser's back button to come back.

How to print one

Open the card, print, and set:

  • Paper: Letter
  • Scale: 100% — not "fit to page", which will shrink the margins away
  • Margins: None
  • Background graphics: On — the black bars are part of the design

Every card says the same thing in a strip along the top, which does not print. The fonts are in the page, so a card printed from a laptop with no internet looks the same as one printed online.

The machine

CardWhat it coversThe chapter it condenses
📄 6502-ACEThe whole machine on two pages: what is on the board, the memory map, the first things to type, and enough BASIC and Monitor to get going. The one that ships with the computerYour ACE
📄 Memory MapAll 64 KB, then RAM and ROM in detail, then every I/O register on the boardThe memory map
📄 ConnectorsEvery socket and header, pin by pin, off the schematicConnectors
📄 Keyboard LayoutThe 67 keys as they sit, and the ones that do something out of the ordinaryThe keyboard
📄 Keyboard MatrixThe 8 × 8 grid behind those keys, with the code each one sendsThe keyboard matrix

The software

CardWhat it coversThe chapter it condenses
📄 BASIC ReferenceEvery keyword with its syntax, the operator table, every error message, and the three traps that catch everyoneEvery keyword
📄 Monitor ReferenceAll seventeen commands, the register display, and G versus JThe Monitor
📄 Kernal Jump TableAll 53 published entry points with their registers, grouped by jobThe Kernal
📄 Character SetAll 256 glyphs drawn from the ROM's own bytes, with names, and what PRINT can actually reachThe character set
📄 F18A RegistersEvery enhanced register on the video card, bit by bit, plus the status registers and the attribute bytesEvery register

That last one is the sheet to have printed rather than open in a tab: F18A mode runs on real hardware only, so the machine you are testing it on is not the machine you would be reading it on.

The KIM add-on

CardWhat it coversThe chapter it condenses
📄 6502-KIMThe three boards, what they overlay, the pad, and the serial monitorThe KIM keypad
📄 Keypad MappingAll twenty-four keycodes and what the LCD shows for eachThe keypad map

Two more sheets have the LED demos laid out to key in, byte by byte: 📄 Binary counter and 📄 KITT scanner.

The rest of the family

Written for someone building one, not using one.

CardMachine
📄 6502-COBThe modular original — a passive backplane and a stack of cards. COB
📄 6502-DEVThe development rig — an emulated CPU you can single-step. DEV
📄 6502-VCSThe console — cartridges and joysticks. VCS

Older BIOS versions

The BASIC and Monitor cards for v1.0 through v1.4 are kept under /cards/archive/. They describe machines whose ROMs are no longer current and are there for anyone running one, not as a second opinion about this one.

Other reference pages

Not cards, but the same job:

Written for BIOS v1.5. Released under the MIT License.