Casio Personal Computer Fx 790p

Casio FX-790P, used calculator, but good conditions. It has one of the hinges broken, see details in the potos. It comes with its original box and manuals in English, all in perfect condition. The one for sale is the one in the photos. Casio Computer Company manufactured desktop calculators with scientific functions from at least 1972, when it sold its FX-1. This machine was sold by Sperry Remington as the Remington 1259S (see 2011.0108.01). In 1974, Casio introduced a handheld scientific calculator, the FX-10 (also sold by Remington as the SSR8). Casio continued to manufacture such calculators as well as simpler devices. Vintage Casio FX-750P personal computer Bienconnu £ 38.40. Casio FX-790P Pocket VintageKammer £ 101.19 FREE UK delivery. Vintage Casio FX-750P personal computer Bienconnu £ 38.40. Casio FX-790P Pocket VintageKammer £ 101.19 FREE UK delivery. Details about CASIO FX-790P - vintage personal computer. CASIO FX-790P - vintage personal computer. Item Information. Condition:-not specified. Price: US $50.00.

The Casio FX-850P is a scientific calculator introduced in 1987 and sold until 1999.

Specifications[edit]

• 2 lines with 32 5×7 characters LCD
  • (some indicators and a 5 digit 7-segment display)
• 8 KB RAM (FX-860P: 24 KB, FX-880P: 32 KB)
• CPU: VLSI at 1.228 MHz. Hitachi HD62002A01 (FX-860P, FX880P: HD62002A03)
• Integrated speaker
• Internal slot for memory expansion (32 KB)
• Connector with support for RS232 and Centronics (only level converter for RS232, Centronics needed)
• LCD Driver: 2 x HD66100F
• 2x 3V CR2032 lithium batteries as main power supply
• 1x 3V CR1220 lithium battery as memory backup (RAM power supply)

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:

Casio Personal Computer Fx 790p Software

• 0000-00FF Screen memory
• 0100-01FF Reserved for internal functions
• 0200-02FF INPUT Buffer
• 0300-03FF CALCJMP, VALF Buffer
• 0400-04FF Reserved for IN/OUT/CALC modes (CALC$)
• 0500-074A Reserved for internal functions
• 074B-0752 Reserved for storing the user PASSWORD
• 0753-175A Reserved for internal functions
• 175B-175C Vector pointing to MEMO memory start
• 175D-1FE4 Reserved for internal functions
• 1FE5-1FFF Vectors pointing to P0-P9 memory start
• 2000-9FFF User memory (shared by MEMO and P0-p))
• A000-BFFF Repetition of 0000-1FFF
• C000-DFFF Repetition of 0000-1FFF
• E000-FFFF Repetition of 0000-1FFF

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:

• POKE 1867,0 → would delete any user PASSWORD
• POKE PEEK(8027)+256*PEEK(8028),32 → would recover contents of MEMO after a RESET ALL
• POKE PEEK(8027)+256*PEEK(8028),26 → would hide contents of MEMO, much like a RESET ALL would do, but without losing the programs

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.

See also[edit]

References[edit]

1. ^http://www.ledudu.com/pockets.asp?type=64&serie=11

External links[edit]

• Casio FX-850P on MyCalcDB Database of 1970s and 1980s pocket calculators

Casio Personal Computer Fx 790p Keyboard