Mark Wickens

Supported Computer Models

The following Casio pocket computers run Casio JIS Standard BASIC. All share the HD61700 CPU and the same core BASIC language, but differ in memory capacity, display size, peripheral support, and available programming languages.

Model Comparison

Model	Base RAM	Max RAM	Display	Graphics	BASIC Lines	Lib	Languages	Katakana	RP Slots
FX-840P	3,536	36,304	2-line	No	2	Fx?			0
FX-841P	3,536	36,304	2-line	No	2	Lib?	STAT		0
FX-850P	3,536	36,304	2-line	No	2	Lib 116		Katakana	1
FX-860P	21,456	54,224	2-line	No	2	Lib 116			0
FX-860Pvc	21,312	54,080	2-line	No	2	Lib 116	CASL		1
FX-880P	21,456	54,224	2-line	No	2	Lib 116		Katakana	1
FX-890P	51,180	83,948	4-line	Yes	4	Fx 3	C, ASM, CASL	Katakana	1
Z-1	18,412	51,180	4-line	Yes	4	Fx 3	C, ASM, CASL	Katakana	1
Z-1GR	18,412	51,180	4-line	Yes	4	Fx 3	C, ASM, CASL	Katakana	1 (RP-33)
VX-1			2-line	No	2				0
VX-2	3,392	36,160	2-line	No	2	Fx 14	CASL	Katakana	1
VX-3	3,355	36,123	4-line	No	4	Fx 3	C, CASL	Katakana	1
FX-870P	17,179	49,947	4-line	No	4	Fx 3	C, CASL	Katakana	1
VX-4	4,891	37,659	4-line	No	4	Fx 3	C, CASL	Katakana	1 (RP-33)
PB-1000			4-line	No	4		ASM, CASL

Notes:

“Base RAM” is the free memory available for programs and data after system overhead
“Max RAM” is the total usable memory with maximum RAM expansion installed
“Lines” refers to the number of physical LCD display lines (the virtual screen is always 8 lines)
“RP Slots” indicates the number of RAM expansion card slots

Model Groupings

For the purposes of this manual, models are grouped by their BASIC command compatibility:

FX-850P / FX-880P Group

The FX-850P (32KB) and FX-880P (64KB) are essentially the same machine with different memory capacities. They feature:

2-line LCD display (32 columns x 2 lines physical, 32 x 8 virtual)
Cassette tape interface via FA-6
PBLOAD/PBGET commands for PB-100 series tape compatibility
VERIFY command for cassette tape verification
SAVE#/LOAD# for data bank cassette operations

FX-870P / VX-4 Group

The FX-870P and VX-4 are the same hardware with different branding. Key differences from the FX-850P/880P:

4-line LCD display (32 columns x 4 lines physical, 32 x 8 virtual)
C language and CASL assembler support
Additional BASIC commands: CHAIN, FILES, KILL, NAME, FORMAT, LINE INPUT#, PRINT USING
Statistical functions: STAT, CNT, SUMX, SUMY, MEANX, MEANY, SDX, SDY, LRA, LRB, COR, EOX, EOY
Hidden MODE110 instruction for machine language execution
MODE200/201 for direct floppy disk sector I/O
No cassette tape interface (RS-232C and floppy disk only)
VERIFY, SAVE#, LOAD#, MERGE#, NEW# commands removed

FX-890P / Z-1 Group

The FX-890P, Z-1, and Z-1GR add graphics capabilities not present in the other models:

Graphics commands: LINE, DRAW, CALL, SWAP, WAIT, REV, NORM
Port I/O: INP, INPORT, OUT, OUTPORT, POINT, TIMER
No cassette tape interface
LB error removed

Peripheral Interfaces

Interface	Models	Notes
FA-6 cassette interface	FX-850P, FX-880P, FX-860P, and earlier	1200 bps, PB-700 compatible format
FA-7 cassette interface	PB-1000	Up to 2400 bps, DIP switch selectable
RS-232C	All models	Serial communication; file transfer and printer output
Floppy disk	FX-870P/VX-4, FX-890P, Z-1	Via external floppy drive unit
RAM expansion (RP-8/RP-33)	Models with RP slots	8KB (RP-8) or 32KB (RP-33) additional RAM

Character Set Differences

The PB-1000 shares the PB-700 character set, which includes special graphics characters. The FX, VX, and Z series use a different extended character set with mathematical and scientific symbols instead. Both character sets share the standard ASCII range (0x20-0x7E).

Internal Encoding

All models use ASCII for internal text encoding. BASIC keywords are stored as single-byte tokens, and line numbers are encoded differently from the earlier PB-700 series. Line numbers can range from 1 to 65,535 (earlier models were limited to 9,999). Programs saved in tokenized format on one model may not load directly on a different model group, though ASCII-format saves (using the , A option) are interchangeable.