Casio FX-601P

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: 6"×3"×½" Display size: 10+2 characters
Weight: 5 oz    
    Entry method: Algebraic with precedence 
Batteries: 2×"CR-2032" Lithium Advanced functions: Trig Exp Hyp Sdev Cmem 
External power:   Memory functions: +/- 
I/O: Casio I/O     
    Programming model: Fully-merged keystroke entry 
Precision: 11 digits Program functions: Jump Cond Subr Lbl Ind  
Memories: 11 numbers Program display: Mnemonic display  
Program memory: 112 program steps Program editing: Auto-insert program entry  
Chipset:   Forensic result: 9.00000716758  

fx601p.jpg (36512 bytes)The FX-601P is one of the most sophisticated programmable calculators from the early LCD era. Coming out on the heels of machines like the legendary HP-41C, it represented a cheaper, yet meaningful alternative to many students and engineers who wished to have a quality instrument at their disposal.

Functionally identical to the FX-602P except for its smaller memory capacity and lack of ability to "partition" memory, the FX-601P has a comprehensive programming model that includes conditionals, subroutines, labels, and even indirect addressing. Its 112-step program memory is a bit cramped, but a fully merged programming model nevertheless provides enough space for relatively sophisticated algorithms to be implemented. Alas, the FX-601P is no longer designed to generate musical tones like its earlier cousin, the FX-501P. However, the calculator's alphanumeric capabilities, including its ability to display program code in mnemonic form, should be more than adequate compensation.

The Gamma function remains my favorite example for programmable calculators. Non-trivial yet simple enough to be implemented on most calculators, it is also a very important mathematical function, used in many statistical calculations, yet it is typically omitted from all but the most sophisticated scientific handhelds.

The following 82-step program neatly demonstrates the calculator's programming model, as it calculates the natural logarithm of the Gamma function for all real arguments to 10+ digits of precision:

001	Min0
002	1
003	Min1
004	5
005	MinF
006	LBL1
007	MR0
008	x>=F
009	GOTO2
010	MR0
011	×
012	MR1
013	=
014	Min1
015	1
016	M+0
017	GOTO1
018	LBL2
019	MR0
020	×
021	ln
022	-
023	MR0
024	+
025	(
026	2
027	×
028	π
029	÷
030	MR0
031	)
032	√
033	ln
034	+
035	(
036	(
037	(
038	(
039	9
040	9
041	1/x
042	÷
043	MR0
044	x2
045	-
046	1
047	4
048	0
049	1/x
050	)
051	÷
052	MR0
053	x2
054	+
055	1
056	0
057	5
058	1/x
059	)
060	÷
061	MR0
062	x2
063	-
064	3
065	0
066	1/x
067	)
068	÷
069	MR0
070	x2
071	+
072	1
073	)
074	÷
075	1
076	2
077	÷
078	MR00
079	-
080	MR01
081	ln
082	=