Casio fx-202P

Datasheet legend
Ab/c: Fractions calculation
AC: Alternating current
BaseN: Number base calculations
Card: Magnetic card storage
Cmem: Continuous memory
Cond: Conditional execution
Const: Scientific constants
Cplx: Complex number arithmetic
DC: Direct current
Eqlib: Equation library
Exp: Exponential/logarithmic functions
Fin: Financial functions
Grph: Graphing capability
Hyp: Hyperbolic functions
Ind: Indirect addressing
Intg: Numerical integration
Jump: Unconditional jump (GOTO)
Lbl: Program labels
LCD: Liquid Crystal Display
LED: Light-Emitting Diode
Li-ion: Lithium-ion rechargeable battery
Lreg: Linear regression (2-variable statistics)
mA: Milliamperes of current
Mtrx: Matrix support
NiCd: Nickel-Cadmium rechargeable battery
NiMH: Nickel-metal-hydrite rechargeable battery
Prnt: Printer
RTC: Real-time clock
Sdev: Standard deviation (1-variable statistics)
Solv: Equation solver
Subr: Subroutine call capability
Symb: Symbolic computing
Tape: Magnetic tape storage
Trig: Trigonometric functions
Units: Unit conversions
VAC: Volts AC
VDC: Volts DC
Years of production: 1977  Display type: Numeric display  
New price:   Display color: Green  
    Display technology: Vacuum fluorescent display 
Size: 7"×4"×1½" Display size: 10(8+2) digits
Weight: 13 oz    
    Entry method: Algebraic 
Batteries: 4×"AA" alkaline + 2×"LR44" button cell Advanced functions: Trig Exp Cmem 
External power: Casio adapter   Memory functions: +/- 
    Programming model: Keystroke entry 
Precision: 10 digits Program functions: Jump Cond Subr Lbl Ind  
Memories: 11 numbers Program display: Keycode display  
Program memory: 127 program steps Program editing: Overwrite capability  
Chipset:   Forensic result: 8.9911614  

Casio fx-202PWhen I acquired my Casio fx-201P, I was under the impression that it was Casio's only early VFD programmable calculator. I've since been proven wrong more than once: it appears that at the time, Casio had an entire family of machines based on this model. One member of this family is the fx-202P, which has the same capabilities as the fx-201P, with one rather important difference: it uses CMOS memory that has a battery backup. In other words, along with HP, Texas Instruments, and Sharp, Casio also had an entry in the market of "continuous memory" programmable calculators in the mid-1970s.

Today is a bright, early spring day made brighter by the fact that the mailman brought me a wonderful gift: a real live working fx-202P! Thank you, Hugh! These rather large-ish scientific calculators somehow manage to convey a sense of magic that is so often missing from later models, no matter how capable.

The fx-201P/202P family uses a rather unusual, programming language like programming model. Highly unusual is the fact that programs are not like interactive keystroke sequences; for instance, if you wish to add 1 to memory register 0, the program would read 0 = 0 + K 1, much more like a procedural language than a keystroke macro.

Back when I first acquired an fx-201P, I explored its capabilities by writing yet another program for the Gamma function, my favorite programming example. Presented here in short form, it neatly demonstrates the calculator's capabilities:

ENT 1 :
2 = K 1 :
ST# 3 :
IF 1 = K 9 : 1 : 2 : 2 :
ST# 1 :
2 = 2 × 1 :
1 = 1 + K 1 :
GOTO 3 :
ST# 2 :
0 = K 1 ÷ K 105 ÷ 1 ÷ 1 :
0 = K 1 ÷ K 30 - 0 ÷ 1 ÷ 1 :
0 = K 1 - 0 ÷ 1 ÷ K 12 :
0 = 1 × ln - 1 + 0 - 2 ln:
2 = K 6.2831853 ÷ 1 :
0 = 2 √ ln + 0:
ANS 0 :