Acorn System 1 User Manual

The Acorn System 1 User's Manual is the tutorial companion to the Acorn System 1 Technical Manual — a course in 6502 machine code written around the System 1's hex keypad and seven-segment display. 80 pages. The scan has no text layer and much of the body is set in upper case throughout.

This is a teaching manual, not a service document. If you are repairing a System 1, the parts lists are in the Acorn System 1 Technical Manual and the values are on the Acorn System 1 Circuit Diagrams. What this manual adds is the one thing those do not: an explanation of what the monitor firmware does and how to drive the machine from the keypad, which is how you test a repaired board.

Contents

Part 1

• Chapter 1 — an introduction to the binary number system: binary numbers, logical manipulations, arithmetic manipulations, BCD arithmetic
• Chapter 2 — welcome to the machine: how the Acorn microprocessor works; the monitor commands M, ↑ and +; a first program (assembly language, machine language, LOAD/STORE/JUMP); entering a program and the GO command; JMP and JSR; ORA and EOR; ADC, SEC and CLC
• Chapter 3 — inside the 6502: accumulator, program counter, status register; the stack pointer; the X and Y registers
• Chapter 4 — the remainder of the instruction set: branches, indexing, indirection, read-modify-write instructions, miscellaneous
• Chapter 5 — Acorn hardware: chip layout and bus; RESET, IRQ and NMI; 6502 internal architecture; PROMs, EPROMs, RAM and RAM/IO; the keyboard and tape interface; power supply
• Chapter 6 — firmware: the tape STORE and LOAD; the breakpoint and restore command; the single stepping facility; the monitor listing

Part 2 — application programs

Appendices — A: 64-character ASCII on Acorn's seven-segment display; B: instruction set; C: hexadecimal to decimal conversion table; D: Acorn monitor address information; glossary

What it settles

Chapter 6 prints the monitor listing and appendix D gives the monitor's address map — between them the only published account of what the System 1's 512-byte monitor ROM actually does. Appendix A's seven-segment character table is what you need to read a display that is showing something other than hexadecimal.

What this manual does not contain

• No parts list, no component values, no circuit diagrams.
• No fault-finding procedures. Chapter 5's hardware description is explanatory, not diagnostic.
• No text layer, so nothing can be searched.

Download here: Acorn System 1 User Manual.pdf

Related pages

• Acorn System 1 · Acorn System 1 Technical Manual · Acorn System 1 Circuit Diagrams · Acorn System 1 Maintenance Guide