Links

The pocket computer museum - an excellent overview of old BASIC programmable calculators and their peripherals.

Programmable Calculators - collection of programmable and non-programmable calculators, complete list of all known programmable calculators.

Old Organizers Collection - high quality photos (including internals), manuals.

silrun Systems - scanned Casio calculator manuals, and freeware program libraries.

New Zealand Casio web site - scanned Casio User Manuals (from main menu select Support -> Document Search).

Casio Utilities - programs to handle tape and floppy disk images from vintage Casio pocket computers.

Casio PB-700 - synthetic programming, table of character and keyword codes, math programs supporting arbitrary precision arithmetic ,(French)

Casio PB-1000 forever! - a reference site (in Japanese)

HD61700 spirits - cross assembler HD61, disassembler DA61, monitor LEMON and other programs for the Casio PB-1000, undocumented assembly instructions (Japanese/English)

Blog about the the Casio FX-870P and VX-4 with, among others, detailed information about the internal resources (system variables and function addresses, memory map, data structures) and the HD61700 assembler (Japanese)

PB-1000 Airbug One - an independent attempt to identify undocumented machine code instructions, disassembler and other programs (French/English)

The Casio PB-1000 Homepage (in German)

Böhling's Casio PB-1000 Website - a lot of programs (in German)

Casio FX-602P Page - a reference site

Casio FX-602P simulator project

Hacked CASIO graphic calculators - reverse engineering the Casio CFX-9850G CPU instruction set, machine code programming on this calculator, several Casio service manuals

Collection of Soviet Calculators

Club of calculator fans - discussion forum, calculator manuals (in Russian)

Museum of Soviet Calculators - among others scanned manuals and the circuit diagram for the Elektronika MK-90.

Soviet electronic technology (in Spanish, under construction)

Soviet calculators - photos, manuals, circuit diagrams, software (in Russian)

High resolution scan of the MK-90 circuit diagram

Elektronika MK-90 hacking page (in Russian)

Games for the Elektronika MK-90 (in Russian)

Blog about the Elektronika MK-90 (in Russian)

Elektronika MK-85 web page (in Russian, abandoned)

Polish web page dedicated to the Elektronika MK-85 - scanned manual, circuit diagram, BASIC programs, modifications (RAM expansion, replacing of the original ROM with a Flash chip, I2C bus interface), repair tips.

History of the development of the Elektronika MK-85 (in Russian)

Free PDP-11 assembler PDPXASM which can be used to write machine code programs for the Elektronika MK-85 and MK-90.

PDP-11 instruction reference - fits the MK-85 and MK-90 as well.

PDP-11 Instruction Set

Description of the HP-35 calculator architecture and firmware, algorithms of elementary math functions. You can join a discussion forum there.