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Casio FX-850P

Casio FX-850P
CASIO FX-850P.jpg
Type Pocket Computer
Manufacturer Casio
Calculator
Entry mode Infix, BASIC,
Display type LCD Dot-matrix
CPU
Processor Hitachi HD62002A01
Programming
Programming language(s) BASIC
User memory 2×32 Character
Interfaces
Ports one vendor specific
Connects to

Compact Cassette via:

Line Printer via one of:

PC via one of:

Other
Power supply 2×"CR2032" Lithium + 1×"CR1220" Lithium

Compact Cassette via:

Line Printer via one of:

PC via one of:

The Casio FX-850P is a scientific calculator introduced in 1987 and sold until 1992.

User's manual at http://www.usersmanualguide.com/casio/calculators/fx-850p

The calculator had a BASIC interpreter, MEMO function, a formula library. The built-in 8 kB memory could be expanded using the optional Casio RP-8 (8 kB) or RP-33 (32 kB) RAM expansion modules. An optional Casio FA-6 interface board provided a cassette tape recorder connector, a Centronics printer connector and an RS-232C port. The calculator could print data and listings on any Centronics printer; printing graphics required the Casio FP-100 plotter-printer.

Later, Casio released the FX-880P, which had 32 kB built-in memory. With a RP-33 expansion module, this model could be upgraded to a total of 64 kB.

The memory layout is:

Memory area A000-FFFF was either available as user memory (if expansion was present), or would simply repeat the contents of 0000-1FFF

A few glitches are:

The internal function library was programmed in BASIC itself and could be extracted with a BASIC decompiler.

Any function in the library can be executed from a regular BASIC program by using GOTO "LIB0:NNNN" where NNNN is the function number (e.g. 5010 for prime factorization). The command GOTO "LIB0:0400" executes a self-test program.

Characters 252 to 255 were user defined. They could be defined by issuing the command DEF CHR$(n)="HHHHHHHHHH" where n ranges from 252 to 255 and the H's are 10 hexadecimal digits (5 bytes). Every byte defines the pixel pattern for a column. Since a column is 7 pixels high, the least significant bit of every byte is ignored.

The CHR$(26) would activate a different character set for Katakana and Kanji characters. CHR$(27) would deactivate Kanji.

Via a serial cable the calculator could connect to a PC or to another Casio FX-850P, allowing the transfer to MEMO and stored programs.


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