Retro Review: Texas Instruments TI-60

Retro Review:  Texas Instruments TI-60

General Information

Company:  Texas Instruments

Type:  Programmable Scientific

Memory:  84 steps or 12 memory registers

Battery:  2 * Duracell MS76, Panasonic WL-14, Eveready 376 or 303, AG-13, SR44

Years:  1986 – 1991

Editions:  2:  1986 (Advanced Scientific), 1990 (Programmable Scientific)

Original Cost: $50

Features

The TI-60 is a scientific keystroke programmable calculator, largely based off of the original TI-55 (1977).  The features of the TI-60:

Operating System:  AOS (Algebraic Operating System)  (like the TI-30Xa)

Programming:  Up to 56 program steps

Statistics:  Linear Regression

Conversions:  °F/°C, DMS/DD, in/cm, lb/kg, gal/L

Base Conversions:  Octal and Hexadecimal, has 2’s complement

Memory Registers: Up to 8, competed with both statistics and programming

Other Functions:  Percent Change, Absolute Value, Signum, Integer Part, Fractional Part

Integration

Shift Keys: 2^nd, hyp, INV

Storage Arithmetic:  +, -, *, ÷, ^, roots, percent change

Percent Key (Δ%) 

I think the percent works backwards than modern calculators.   Press the new value first, then [2^nd] [ . ] ( Δ% ), then old value, [ = ].

Example:  Percent change from 32 to 56:  56 [2^nd] [ . ] (Δ%) 32 [ = ] 75  (75% increase)

Combinations and Permutations

Like the TI-55 III, the arguments for combination and permutation functions take one argument in the form of nnn.rrr.  

Example:

Combination where n = 25, r = 5 is entered as 25.005 [2^nd] [ + ] (nCr)  

(Result: 53,130)

Permutation where n = 25, r = 5 is entered as 25.005 [2^nd] [ = ] (nPr)  

(Result:  6,375,600)

Rectangular/Polar Conversion

[2^nd] [x<>y] (P-R):  to Rectangular.  Input:  r [x<>y] θ [2^nd] [x<>y] (P-R).  Result: y [x<>y] x.

[INV] [2^nd] [x<>y] (P-R):  to Polar.   Input x [x<>y] y [INV] [2^nd] [x<>y] (P-R).  Result:  θ [x<>y] r.

Linear Regression

The TI-60 has the parts labeled Intcp (y-intercept) and Slope. Running the statistics mode reduced the maximum number of steps to 20 until the statistics registers were cleared.

TI-60 vs TI-55 III

TI-60	TI-55 III
84 maximum steps or 12 memory registers	56 maximum steps or 8 memory registers
Clear programs outside of Learn mode	Clear programs inside of Learn mode
Each step you keyed is displayed in a PC(step #)  OP(key code #) format	After each step, display is advanced to next available step, have to press BST to view what you just did, like the TI-58 series
Base Mode:  Octal and Hexadecimal	No base mode
The RST (reset) instruction loops to Step 00	The RST (reset) instruction stops execution, directs program to Step 00

Verdict

I wish TI had implemented this keystroke system earlier.  I like the fact that the RST instruction allowed for loops.  I like that the user can see what was pressed after each step. 

The TI-60 came at the tail end of the keystroke programmable calculators for Texas Instruments.  The keys are a pleasure a press, the contrast of the fonts is for the most part, excellent, except for the gray 1/x and √ 2^nd functions on a gray background.

For the keystroke calculators from Texas Instruments, the TI-60 one of my favorite, second to the TI-58C. 

Eddie

This blog is property of Edward Shore, 2018.

The Calculator Minimalist Programming Club

The Calculator Minimalist Programming Club

When you are in the mood to program only the quickest calculations and you don’t need all the bells and whistles, check out these vintage and modern calculators from minimalist programming club. In attempt to minimize the amount of words said, we’re just going to start.

Top: Radio Shack EC-4004, Casio fx-3600g, Casio fx-3650p; Bottom:  Radio Shack EC-4036, Texas Instruments TI-55 III, Active RPN app on my iPod Touch

A screen shot of the Active RPN app

Top Row:

Calculator	Radio Shack EC-4004	Casio fx-6300g	Casio fx-3650p
Type	Programmable	Graphing	Solar Programmable
Year Originated (approximate)	1981	1991	2013
Forensic Value	9.00015718	9.00015685	8.999998637
Batteries	LR 1130	2 CR 2032	1 LR 44 (backup)/Solar
Number of Storage Bytes	38	400	360
Number of Programming Spaces	2	10	4
Notes	Has six memory registers (Kin/Kout) Linear Regression Simple Loops (go back to step 1 if test fails) RTN ends programs “Blind” programming	26 Registers (A-Z) Memory can be fragmented Linear Regression Can graph functions (y(x)) Base operations (BIN, DEC, OCT, HEX) Loops: Isz, Dsz, Goto, Lbl, Jump Fractions	7 Variables (A, B, C, D, X, Y, M) 6 Regressions (Linear, Logarithmic, Exponential, Power, Inverse, Quadratic) Base operations (BIN, DEC, OCT, HEX) Loops: Isz, Dsz, Goto, Lbl, Jump Fractions, Integrals, Derivatives, Separate Complex Mode (arithmetic, arg, abs, conjugate only)

Bottom Row:

Calculator	Radio Shack EC-4036 (also Citizen SRP-45)	Texas Instruments TI-55 III	Active RPN iOS App
Type	Programming	Programming	Programming
Year Originated (approximate)	1991 (Citizen)	1986	2010
Forensic Value	9.00001562	9.1146406	9.000417
Batteries	2 RS 357A	2 A76	N/A
Number of Storage Bytes	40	56*  Partitioned with memory registers	80
Number of Programming Spaces	1	1	4
Notes	“Blind” programming Integer function - not (see below) (program only) Halt (Pause, R/S)	“Blind” programming but back and forward step are available Integer, Fraction, Sign, Absolute value functions Linear Regression Combinations/Permutations require a n.rrr format Integration (must have 3 memory registers, max of 40 programming steps)	Programs can be edited via text codes (key numbers) Music/beeps can be turned on No statistics Entire four-level stack is shown at once

On the EC-4036, it turns out that  [ x ] is NOT the integer function.  [ x ] acts like a input prompt.  Programming with [ x ] gives a prompt [ n ].    Also, [HALT] just halts the calculator to show what is on the display.  Source:  Citizen SR145N manual, which is very similar to the EC-4036.  

Forensic Value =  asin( acos( atan( tan( cos( sin( 9°))) )))

This test is common.

“Blind” programming:  You don’t see an indicator that your step has been accepted.  In the case of the EC-4004 and EC-4036, there is no editing. 

Thanks to Jose Mesquita from the MoHPC Calculator forum for posting on the Citizen SRP-45, an equivalent of the Radio Shack EC-4036.  Link: http://www.hpmuseum.org/forum/thread-6200-post-66474.html#pid66474

There are the first (and only?) inductees to the Calculator Minimalist Programming Club. 

Have a great day, and may your troubles be minimized,

Eddie

This blog is property of Edward Shore, 2017.

Video: TI-55 III Integration Demo

Video:  TI-55 III Integration Demo

Link:  https://www.youtube.com/watch?v=YLYJYX3EHd4&feature=youtu.be

This blog is property of Edward Shore, 2016

TI-55 III Programs Part III: Area and Eccentricity of Ellipses, Determinant and Inverse of 2x2 Matrices, Speed of Sound/Principal Frequency

TI-55 III Programs Part III:  Area and Eccentricity of Ellipses, Determinant and Inverse of 2x2 Matrices, Speed of Sound/Principal Frequency

For Part I, click here:  Digital Root, Complex Number Multiplication, Escape Velocity

For Part II, click here:  Impedance of a Series RLC Circuit, Quadratic Equation, Error Function  

TI-55 III:  Area and Eccentricity of the Ellipse

Formulas:

Assume a>b, where a and b represent the lengths of semi-diameters, respectively

Area:  A = π*a*b

Eccentricity:  ϵ = √(1 – (b/a)^2)

Program: 

Partitions Allowed: 1-5

STEP	CODE	KEY	COMMENT
00	71	RCL	R0 = a
01	00	0
02	65	*
03	71	RCL	R1 = b
04	01	1
05	65	*
06	91	π
07	95	=
08	12	R/S	Display A
09	53	(
10	01	1
11	75	-
12	53	(
13	71	RCL
14	01	1
15	55	÷
16	71	RCL
17	00	0
18	54	)
19	18	X^2
20	54	)
21	95	=
22	13	√
23	12	R/S	Display ϵ

Input:  a [STO] 0, b [STO] 1, [RST] [R/S]

Result:  Area, [R/S] Eccentricity

Test:  a = 7.06, b = 3.78

Result: A ≈ 83.839055, ϵ ≈ 0.8445918

TI-55 III:  Determinant and Inverse of 2 x 2 Matrices

This program will require 4 registers. 

Input Matrix:  M = [[ R0,  R1 ] [ R2 , R3 ]]

Output Matrix:  M^-1 = [[ R3/det, -R1/det ] [ -R2/det, R0/det ]]

Where det = R0 * R3 – R1 * R2  (determinant). 

Program: 

Set 4 partitions:  [2^nd] [LRN] (Part) 4

STEP	CODE	KEY	COMMENT
00	71	RCL	Calculate determinant
01	00	0
02	65	*
03	71	RCL
04	03	3
05	75	-
06	71	RCL
07	02	2
08	75	*
09	71	RCL
10	01	1
11	95	=
12	12	R/S	Display determinant
13	61	STO	Calculate inverse
14	55	÷
15	00	0
16	61	STO
17	55	÷
18	03	3
19	94	+/-
20	61	STO
21	55	÷
22	01	1
23	61	STO
24	55	÷
25	02	2
26	01	1	Display 1 to indicate “done”
27	12	R/S

Input:  Store:

M(1,1) [STO] 0

M(1,2) [STO] 1

M(2,1) [STO] 2

M(2,2) [STO] 3

Press [R/S] to calculate the determinant of M.  If M≠0, continue and press [R/S].

You will see a 1 in the display, this is used as an indicator that the program is done. 

Result Inverse Matrix:

M^-1[1,1] stored in R3

M^-1[1,2] stored in R1

M^-1[2,1] stored in R2

M^-1[2,2] stored in R0

Test: 

M =  [ [ -1.4,  3.0 ], [ 2.8, 6.4 ] ]

Determinant = -17.36

M^-1 ≈  [ [ -.3686635945, .1728110599 ], [ .1612903226, .0806451613 ] ]

TI-55 III: Speed of Sound/Fundamental Resonant Frequency

Formulas:

Speed of Sound (m/s):  v = t*0.6 + 331.4

Where t = temperature (°C)

Fundamental Resonant Frequencies in an Open Pipe:  fn = v/(2*L)

Where fn = frequency (Hz), v = speed of sound (m/s), L = length of pipe (m)

Program:

Partitions allowed:  1-5

STEP	CODE	KEY	COMMENT
00	65	*
01	93	.	Decimal point
02	06	6
03	85	+
04	03	3
05	03	3
06	01	1
07	93	.	Decimal point
08	04	4
09	95	=
10	12	R/S	Display speed of sound
11	55	÷
12	02	2
13	55	÷
14	12	R/S	Prompt for L
15	95	=
16	12	R/S	Display frequency

Speed of Sound in Dry Air: 

Input:  Enter temperature in °C [F1]

Result:  Speed of sound (m/s), press [R/S]

Fundamental Resonant Frequencies:

Store the length of the open pipe (m) then press [R/S]

Result:  Fundamental Resonant Frequency (Hz)

Test:

Open pipe of 0.45, where the temperature of the air is 39°C (102.2°F). 

Input:  39 [R/S]

Result:  354.8 m/s (speed of sound), [R/S]

394.22222 Hz (fundamental resonant frequency)

Source:  Browne Ph. D, Michael.  “Schaum’s Outlines:  Physics for Engineering and Science”  2^nd Ed.  McGraw Hill: New York, 2010

 Eddie

I hope you are enjoying this series of programs for calculators from the 1980s.  The next series, I plan to stay in the 1980s when I work with the 1988 HP 42S.

This blog is property of Edward Shore.