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DATAMATH CALCULATOR MUSEUM

CASIO FX-501P

Date of introduction:	October 1979	Display technology:	LCD
New price:		Display size:	10 + 2
Size:	5.7" x 2.8" x 0.45" 144 x 71 x 11 mm³
Weight:	3.3 ounces, 94 grams	Serial No:
Batteries:	2*LR44	Date of manufacture:	mth 10 year 1979
AC-Adapter:		Origin of manufacture:	Japan
Precision:	11	Integrated circuits:	CPU: HD43108A RAM, DISPLAY: HD43109
Memories:	22
Program steps:	256	Courtesy of:	Ken H. Meine

Casio Computer Co., Ltd introduced with the FX-501P and FX-502P in October 1979 their first keystroke Programmable Pocket Calculator with LC-Display following the amazing PRO fx-1, trailing Hewlett Packard's legendary HP-41C about three months. The main differences between the FX-501P and FX-502P are the capacity of the user memory:

• FX-501P: 128 merged program steps, 11 user memories
• FX-502P: 256 merged program steps, 22 user memories

Both FX-501P and FX-502P shared their crowded keyboard and were succeeded in March 1981 with the FX-601P and FX-602P, introducing a dot matrix LC-Display and laying the foundation for the FX-702P "Pocket Computer".

The FX-501P series of Programmable Pocket Calculators features a 7-pin connector for peripherals positioned next to the coin batteries on top of the housing:

Product	Description	MSRP (1979)
FA-1	Cassette Interface

Dismantling the featured Casio FX-501P manufactured in October 1979 by Casio Computers in Japan reveals a surprisingly clean design centered around a custom-specific 4-bit microcontroller HD43108A and one support chip:

• HD43108A: 4-bit microcontroller with integrated RAM and ROM manufactured by Hitachi in a CMOS process and using
a 56-pin QFP (Quad Flat Pack) package
• HD43109: Display driver with built in RAM, manufactured by Hitachi in a CMOS process and using
a 60-pin QFP (Quad Flat Pack) package

If you have additions to the above article please email: joerg@datamath.org.