Sharp PC-1201

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: 1978?  Display type: Numeric display  
New price: USD 90.00   Display color: Green  
    Display technology: Vacuum fluorescent display 
Size: 6"×3"×1" Display size: 10+2 digits
Weight: 10 oz    
    Entry method: Algebraic 
Batteries: 2×"AA" alkaline + 2×"LR44" button cell Advanced functions: Trig Exp Lreg Cmem Snd 
External power: Sharp EA-17E adapter   Memory functions:
I/O: Diagnostic port     
    Programming model: Fully-merged keystroke entry 
Precision: 12 digits Program functions: Jump Cond Subr Lbl  
Memories: 12 numbers Program display: Keycode display  
Program memory: 128 program steps Program editing: Insert/delete capability  
Chipset:   Forensic result:  

pc1201.jpg (34711 bytes)One of the rarest programmable machines in existence, the Sharp PC-1201 is Sharp's first entry into the programmable calculator market.

Although it is labelled a "POCKET COMPUTER", the PC-1201 is a classic keystroke programmable calculator. And, I am surprised to find, a very good one at that! The specimen in my hand, despite its advanced age, works perfectly, with a good quality keyboard, crisp display, and last but not least, flawlessly functioning continuous memory.

Continuous memory? Yes indeed! The PC-1201 turns out to be the only pre-LCD programmable not made by Texas Instruments or Hewlett Packard that has this feature. All 128 program steps and 12 memories are preserved when the calculator is turned off. Moreover, the machine's memory receives backup power from two button cells, ensuring that memory contents are not lost when the main batteries are discharged or removed.

All in all, this is a very nice calculator. (Just why is it that in the calculator market, everything seems to be downhill since the days of the early classic machines?) Its programming model is a fully merged keystroke model, with a well organized keycode display (for instance, the 3-key sequence F LBL 0 is displayed as F-13-00 in program memory.)

To demonstrate the programming model of the PC-1201, here's my favorite example, the Gamma function. The program below computes the natural logarithm of the Gamma function to 8 or more digits of precision:

000	F-13-00	LBL 0
001	55-00	x->M 0
002	01	1
003	55-01	x->M 1
004	04	4
005	55-83	x->M t
006	F-13-01	LBL 1
007	65-00	RM 0
008	54	×
009	65-01	RM 1
010	84	=
011	55-01	x->M 1
012	01	1
013	75-00	M+ 0
014	65-00	RM 0
015	F-85-01	x<t 1
016	54	×
017	33	ln
018	64	-
019	65-00	RM 0
020	64	-
021	65-01	RM 1
022	33	ln
023	74	+
024	42	(
025	02	2
026	54	×
027	F-41	π
028	44	÷
029	65-00	RM 0
030	43	)
031	F-42	√
032	33	ln
033	74	+
034	42	(
035	01	1
036	01	1
037	08	8
038	08	8
039	F-43	1/x
040	44	÷
041	65-00	RM 0
042	F-44	x2
043	64	-
044	01	1
045	06	6
046	08	8
047	00	0
048	F-43	1/x
049	44	÷
050	65-00	RM 0
051	F-44	x2
052	74	+
053	01	1
054	02	2
055	06	6
056	00	0
057	F-43	1/x
058	44	÷
059	65-00	RM 0
060	F-44	x2
061	64	-
062	03	3
063	06	6
064	00	0
065	F-43	1/x
066	44	÷
067	65-00	RM 0
068	F-44	x2
069	74	+
070	01	1
071	02	2
072	F-43	1/x
073	44	÷
074	65-00	RM 0
075	43	)
076	84	=
077	85	S/E