Compucorp 322G Scientist

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: 1972-1975 Display type: Numeric display  
New price: USD 795.00   Display color: Orange  
    Display technology: Plasma fluorescent display 
Size: 9"×5½"×3" Display size: 10+2 digits
Weight: 4 lbs    
    Entry method: Algebraic 
Batteries: 4×"D" alkaline Advanced functions: Trig Exp 
External power: 7VDC 1.3A   Memory functions: +/-/×/÷/^ 
    Programming model: Keystroke entry 
Precision: 13 digits Program functions:  
Memories: 10 numbers Program display:  
Program memory: 80 program steps Program editing:  
Chipset:   Forensic result: 8.999998638082  

cc322g.jpg (47484 bytes)The Compucorp 322G Scientist is a lower-end version of the 324G calculator. Instead of two program storage areas holding 80 program steps each, it only has one. Otherwise, the two machines are identical.

This poor machine shown on the right here was initially non-functional. Although it showed a heartbeat on my oscilloscope, nothing appeared on its display. At first, I suspected that the problem is with the display itself but then I came across another dysfunctional Compucorp machine, and when I swapped displays, the 322G failed to come to life. As it turns out, the problem was due to a faulty memory board; once replaced, the 322G was functioning correctly.

I can't help it, I just love these old machines. Their elegant design, the beautiful orange display, the quality engineering reminds one of bygone era; the era of Saturn V rockets reaching for the Moon, that is.

The biggest omission in the 322G's programming model is the lack of any conditional transfer functions. The machine's 80 program steps would be far better utilized if one had the ability to implement simple control structures and loops. That said, some simple control structures canbe implemented by using two peculiar features of this machine. First, that programs containing no halt instruction are executed endlessly (i.e., after the last step, program execution doesn't stop but resumes at the first step in program memory). Second, programs are halted when an error condition is encountered. These two facts can be used together to implement simple looping constructs.

This is demonstrated by the following program that computes the factorial of the argument on display, depositing the result in register 1. The result can be retrieved after clearing the display (remember, the program stops with an intentionally triggered error condition.)

 01    STn
 02    1
 03    1/x
 04    RCLn
 05    1
 06    ×
 07    STn
 08    0
 09    (
 10    RCLn
 11    1
 12    -
 13    1
 14    )

I've also written a more complex programming example, demonstrating the generalized factorial, also known as the Gamma function, for the 324G.