TI-59 magnetic card

File Format
Name	TI-59 magnetic card
Ontology	Physical File Formats Magnetic stripe card TI-59 magnetic card
Released	1977

The TI-59 was a programmable calculator from Texas Instruments which was available from 1977 through 1983. It supported the ability to load and save programs using a magnetic-stripe card reader. The TI-58 model was also available at the same time with similar programming features but no card reader. An earlier TI-57 model was also programmable but with more limited features and memory and no storage device to permanently save the programs.

If you ran out of magnetic cards for it, it was apparently possible to make new ones by cutting up floppy disks.

The TI-59 had 120 storage registers, divided between program and data memory. They were divided into four banks of 30 registers, and one bank could be stored on a side of a magnetic card, for a total of two banks per card if both sides were used. Thus it took both sides of two cards to store the entire contents of the calculator. Each storage register could hold one floating-point numeric value or 8 program key codes.

The card reader used a four-track head designed to function at a speed between 2.0 and 2.5 inches per second. Track one is closest to the edge of the card. The write signal is a square wave of ± 1.5 V.

The TI-59 also had a place to insert firmware chips which contained library routines which could be used in programs.

Character/Key Codes

Each key, character, or function on the calculator corresponded to a numeric code of two decimal digits. (How, exactly, this translated into particular magnetic pulses on the card is uncertain.)

Code	Key	Description
00	0	Number keys
01	1
02	2
03	3
04	4
05	5
06	6
07	7
08	8
09	9
10	E'	Function keys
11	A
12	B
13	C
14	D
15	E
16	A'
17	B'
18	C'
19	D'
20	2nd CLR	Clear All?
21	2nd	Shift to alternate function
22	INV	Inverse
23	LNx
24	CE	Clear entry
25	CLR	Clear
26	2ND
27	INV	Inverse function
28	LOG
29	CP	Clear Program
30	TAN	Tangent
31	LRN	Learn
32	X:T	Exchange X with T
33	X2
34	√X
35	1/X
36	PGM	Program (followed by 2-digit number of library program, stored in 1 item)
37	P/R	Polar to Rectangular
38	SIN
39	COS
40	IND	Indirect (followed by 2-digit memory location, stored in 1 item; uses contents of that as memory location to finally access)
41	SST	Single-Step
42	STO	Memory store (followed by 2-digit memory location, stored in 1 item)
43	RCL	Memory recall (followed by 2-digit memory location, stored in 1 item)
44	SUM	Memory sum (followed by 2-digit memory location, stored in 1 item)
45	YX
46	INS	Insert program line
47	CMs	Clear data memory
48	EXC	Memory exchange (followed by 2-digit memory location, stored in 1 item)
49	PRD	Memory product (followed by 2-digit memory location, stored in 1 item)
50	|x|	Absolute value
51	BST
52	EE	Enter exponent
53	(
54	)
55	÷
56	DEL	Delete program line
57	ENG	Engineering notation
58	FIX	Fix decimal
59	INT	Integer
60	DEG	Degrees
61	GTO	Goto (followed by two-digit label number, stored in one position)
62	PG*
63	EX*
64	PD*
65	×
66	PAU	Pause
67	X=T
68	NOP	No-Op
69	OP	Special operations (followed by two-digit function code, stored in one position)
70	RAD	Radians
71	SBR	Subroutine
72	ST*
73	RC*
74	SM*
75	-
76	LBL	Label (followed by two-digit label number, stored in one position)
77	X≧T
78	∑+
79	X-bar	Mean
80	GRD	Grads
81	RST
82	HIR
83	GO*
84	OP*
85	+
86	STF
87	IFF
88	D.MS	Degrees/Minutes/Seconds
89	π	Pi
90	LST	List data registers on printer
91	R/S	Run/Stop
92	RTN	Return from subroutine
93	.
94	+/-
95	=
96	WRT	Write to magnetic card
97	DSZ	Decrement and skip at zero
98	ADV	Printer paper advance
99	PRT	Print

References

• TI-59 / TI-58 (Wikipedia)
• TI-59 "fan page"
• TI manuals and documentation
• Calculator museum entry
• TI-59 Service Manual (lots of useful low-level tech stuff here)
• TI59 emulator download (for Windows)