!!!Acorn Atom
{{outline}}

!!Specifications
*CPU
**MOS Technology 6502 @ 1MHz
*ROM
**8KB(max:12KB)
*RAM
**2KB(max:12KB) ¢¨VRAM¹þ¤ß
*VRAM
**1KB (max:6KB)
*Video
**MC6847
*Sound
**1ch

!!Memory Map

,Address,Size,
,$0000~$00FF,0.25KB,Zero page
,$0100~$01FF,0.25KB,Stack
,$0200~$03FF,0.5KB,RAM (expansion)
,$0400~$07FF,1KB,Teletext VDG RAM (expansion)
,$0800~$08FF,0.25KB,VDG CRT Controller (expansion)
,$0900~$09FF,0.25KB,RAM (expansion)
,$0A00~$0A04,-,"8271 (FDC, optional)"
,$0A80~$0FFF,1.5KB,RAM (expansion)
,$1000~$1FFF,4KB,Peripherals space
,$2000~$21FF,0.5KB,Catalogue buffer
,$2200~$27FF,1.5KB,Sequential File buffers
,$2800~$28FF,0.25KB,Floating point variables
,$2900~$3BFF,4.75KB,Extension Text space RAM
,$3C00~$7FFF,17KB,Off-board Extension RAM
,$8000~$83FF,1KB,VRAM
,$8400~$97FF,5KB,VRAM
,$9800~$9FFF,2KB,RAM (expansion)
,$A000~$AFFF,4KB,Utility ROM (optional)
,$B000~$B003,-,Intel 8255 (PPI)
,$B004~$B7FF,2KB,(reserved)
,$B800~$BBFF,1KB,VIA 6522
,$BC00~$BFFF,1KB,(reserved)
,$C000~$CFFF,4KB,ATOM BASIC Interpreter
,$D000~$DFFF,4KB,Extension ROM (optional)
,$E000~$EFFF,4KB,Disk Operating System (optional)
,$F000~$FFFF,4KB,Assembler/Cassette Operating System

!!I/O

!!!8255
,Address,bit,I/O,
,$B000,7~4,O,Graphics mode
,,3~0,O,Keyboard row
,$B001,7,I,SHIFT key
,,6,I,CTRL key
,,5~0,I,Keyboard column
,$B002,7,I,60Hz input
,,6,I,REPT key
,,5,I,Cas input
,,4,I,2.4KHz input
,,3,O,Color set
,,2,O,Buzzer
,,1,O,Enable 2.4KHz
,,0,O,Cas output

!!BASIC

[ATOMIC THEORY AND PRACTICE|http://members.casema.nl/hhaydn/howel/Acorn/Atom/atap/atap.htm]

!!!Commands

 LIST, LOAD, NEW

!!!Functions

 ABS, BGET, 0 CH, COUNT, EXT, FIN, FOUT, GET, LEN, PTR, RND, TOP

!!!Connectives

 AND, OR, STEP, THEN, TO

!!!Statements

 BPUT, CLEAR, DIM, DO, DRAW, END, FOR, GOSUB, GOTO, IF, INPUT, LET, LINK, MOVE, NEXT
 OLD, PLOT, PRINT, PUT, REM, RETURN, RUN, SAVE, SGET, SHUT, SPUT, UNTIL, WAIT

!!!Operators

 !, #, $, &, *, +, -, /, :, < =, >, ?, \, <>, < >=

!!Links
* [Acorn Atom|https://en.wikipedia.org/wiki/Acorn_Atom] / Wikipedia
* [AtomSoftwareArchive|https://github.com/hoglet67/AtomSoftwareArchive]

!!!Emulators
* [ATOMULATOR|http://atomulator.acornatom.co.uk/]
* [Acorn Atom Emulator|http://www.stairwaytohell.com/atom/wouterras/]
* [Acorn Atom Emulator|http://www.iwriteiam.nl/Ha_Atom.html]