Radio Shack PC-1

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:   Display type: Alphanumeric display  
New price:   Display color: Black  
    Display technology: Liquid crystal display 
Size: 3"×7"×½" Display size: 24 characters
Weight: 6 oz    
    Entry method: BASIC expressions 
Batteries: 4×"LR44" button cell Advanced functions: Trig Exp Cmem Snd 
External power:   Memory functions:  
I/O: Printer port     
    Programming model: BASIC 
Precision: 12 digits Program functions: Jump Cond Subr Lbl Ind  
Memories: 2200(0) bytes Program display: Text display  
Program memory: 2200 bytes Program editing: Text editor  
Chipset: Sharp PC-1211   Forensic result: 8.99998153428  

trs80.jpg (27965 bytes)This beautiful machine, Radio Shack's first pocket computer/calculator, dates back to the earliest days of low cost commercial LCD displays, characterized by the yellow color of the UV filter designed to protect the liquid crystal.

Like most other Radio Shack/Tandy calculator products, this one is also an OEM machine, the Sharp PC-1211 in disguise. Over the years, Sharp made many BASIC programmable pocket calculators and computers that followed this same basic design.

Just recently I repaired a PC-1211 that has been in my box of defective calculators since ages. To test the machine, I wrote yet another implementation of the Gamma function for it, the program I prefer to use as a demonstrative example:

110:S=SGN Z
120:X=ABS Z
140:IF X>5THEN 180
170:GOTO 140
180:G=X*LN X-X+LN (√(2π/X)/G)+((((1/99/X/X-1/140)/X/X+1/105)/X/X-1/30)/X/X+1)/X/12
190:IF S>0THEN 220
210:G=LN (-π/Z/SIN πZ)-G
220:PRINT "LNG(Z)=",G