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Texas Instruments TI-1050

Date of introduction:	June, 1977	Display technology:	Fluorescent
New price:	$12.95, £9.95	Display size:	8
Size:	5.4" x 2.9" x 1.3"
Weight:	5.1 ounces	Serial No:
Batteries:	9V	Date of manufacture:	wk 12 year 1978
AC-Adapter:	AC9180	Origin of manufacture:	El Salvador
Precision:		Integrated circuits:	TMC0921
Memories:	1
Program steps:		Courtesy of:	Joerg Woerner

Introduced together with the TI-1000 this one uses a fluorescent display and some enhanced features. In a direct comparison with the TI-1025 you'll notice the unusual [M], [MR] and [REV]-keys. At first glance you would expect only limited memory functions and an exchange functions between the memory and display known from the TI-2550-III but Colin Douglas Howell located the US Patent Application #4112495.

This patent includes a complete ROM listing of the code in the TMC0921 single-chip calculator circuit used by TI-1050. Unfortunately, the listing is rather poorly printed, but there are a couple other patents, #4100606 and #4287559, which include clearer printouts of the same code. The code, once deciphered, is rather interesting, and it serves as a useful guide to the details of both the TI-1050 and the TI-1025, which used the closely related TMC0923.

This code reveals that the TI-1050's [M] key is a prefix key that allowes it to perform various memory operations, including the following:

[M] [CE/C]	Clear Memory
[M] [=]	Store Display in Memory
[M] [+]	Add Display to Memory
[M] [-]	Subtract Display from Memory
[M] [x]	Multiply Memory by Display
[M] [/]	Divide Memory by Display
[M] [REV	Exchange Memory with Display

The approach of a memory prefix key was continued with the TI-1680, its twin TMS-2550-IV and the later TI-1070.

The TI-1050 calculators were manufactured either in El Salvador, Hong Kong, Italy or USA.

Calculators with different nameplates were sold from Western Auto as Citation.

If you have additions to the above article please email: joerg@datamath.org.