Casio FX-702P

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: 1981  Display type: Alphanumeric display  
New price:   Display color: Black  
    Display technology: Liquid crystal display 
Size: 3"×6½"×½" Display size: 12 characters
Weight: 6 oz    
    Entry method: BASIC expressions 
Batteries: 2×"CR-2032" Lithium Advanced functions: Trig Exp Hyp Lreg Cmem Snd 
External power:   Memory functions:  
I/O: Casio I/O, expansion slot     
    Programming model: BASIC 
Precision: 12 digits Program functions: Jump Cond Subr Lbl Ind  
Memories: 1680(0) bytes Program display: Text display  
Program memory: 1680 bytes Program editing: Text editor  
Chipset:   Forensic result:  

fx702p.jpg (33063 bytes)I believe that the FX-702P was one of the very first BASIC programmable handheld calculators made by Casio. This early machine has several unique distinguishing features. First, its external interface is a 7-pin plug that is identical to that used on the fx-602P, and decidedly different from the wider plugs used in many later machines. Second, its programming model: it includes non-standard keywords such as INP or PRT, and a rich set of scientific functions (e.g., hyperbolic functions, 2-variable statistics) not normally found on BASIC handhelds. Even its keyboard layout is different: instead of a QWERTY layout, letters of the alphabet are arranged in sequential order.

That said, I kind of like this machine. Maybe it's that "retro" spirit in me, but I find this machine more friendly than later, slimmer Casio models.

That said, I kind of like this machine. Maybe it's that "retro" spirit in me, but I find this machine more friendly than later, slimmer Casio models.

Since this machine has a built-in hyperbolic sine function, it is only appropriate to demonstrate its programming model using an approximation of the logarithm of the Gamma function, developed by Robert H. Windschitl, which uses the hyperbolic sine for a fast and efficient computation:

10 INP "X",X
20 G=1
30 S=SGN X
40 Z=ABS X
50 IF Z>9 THEN 90
60 G=G*Z
70 Z=Z+1
80 GOTO 50
90 G=LN (Z*SQR (Z*HSN (1/Z)+1/810/Z^6))*Z-Z+LN (2*π/Z)/2-LN G
100 IF S>0 THEN 120
110 G=LN (-π/X/SIN (π*X))-G