Datamath Calculator Museum DCM-50A (TMS1000)

Date of introduction:  September 21, 2022 Display technology:  LED
New price:  $849.95 (2022 = $119.95 in 1972) Display size:  12
Size:  10.5" x 8.5" x 1.5"
 267 x 216 x 38 mm3
Weight:  17.4 ounces, 494 grams Serial No:  0001
Batteries:  4*AA Date of manufacture:  mth 09 year 2022
AC-Adapter:  DC 6V Origin of manufacture:  USA
Precision:   Integrated circuits:  ZIF-Sockets for TMS1000, TMS1040 Adapter, TMS1070, 3*SN75493, 2*SN75494
Memories:   Displays:  HP 5082-7653
Program steps:   Courtesy of:  Joerg Woerner

The Datamath Calculator Museum DCM-50A (TMS1000) is based on the generic DCM-50A Platform to access all features of calculators based on Texas Instruments single-chip calculator circuits and covers designs based on:

TMS1000 Family
TMS1040 Family
TMS1070 Family

With many of the single-chip calculator circuits either designed for Texas Instruments' proprietary applications or developed for OEM manufacturers, available documentation of their features is rather scarce and we are committed to provide as much information as possible to the calculator enthusiasts and we document our observations and findings here.

The Technology Section of the Datamath Calculator Museum features under Calculator Chips "Datasheets" of the mentioned product families.

Characterization of Single-chip Calculator Circuits

TMS1040 Family

The DCM-50A Platform supports the Characterization of TMS1040 Devices in its right-most TMS1000 Textool Test Socket using an additional TMS1040 Adapter and the voltages VSS set to 9.5V and VDD/VGG set to -5.5V, accordingly. The TMS1040 Adapter hosts an additional voltage regulator to provide VDD (-9V) and VPP (-15V) to the TMS1040 Textool Socket. Additional means on the TMS1040 Adapter are providing both the optional "Virtual" K10 Keyboard Input and "Slide Switches / Diode Jumper" Keyboard Inputs used with some TMS1040 calculator designs.


TMS1042NL - Canon LD-8Rs (October 1976) including LD-8s and LD-8Ms
TMS1042NL - Sharp EL-8117K (April 1977)
TMS1043NL - TI-2550 III (September 1976)
TMS1043BNL - TI-2550 III (October 1977)
TMS1044NL - Bohsei Model 1000 (September 1977) and Exploration Privileg 858 MD
TMS1044NL - Brinlock Model 806 (June 1980)
TMS1044NL - Unisonic Model 1040-1 (December 1977)
TMS1045NL - Canon F-31 (June 1977)
TMS1045NL - Canon L813 (May 1978)
TMS1045NL - Canon L813 II (August 1984)
TMS1045NL - Toshiba BC-8111B (January 1980)

TMS1070 Family

The DCM-50A Platform supports the Characterization of TMS1070 Devices in its right-most TMS1000 Textool Test Socket with patching of Pin 20 and Pin 21 and the voltages VSS set to 9.5V and VDD/VGG set to -5.5V, accordingly with the MOS-Load resistors tied to VDD, simulating the low-voltage Vacuum Fluorescent Displays (VFDs) used with all TMS1070 calculator designs.


TMS1071NL - TI-2550 II (March 1976)
TMC1073NL - TI-5100 (December 1981)
TMC1073NL - Toshiba BC-1015 (April 1979)
TMC1079NL - Canon Palmtronic MD-8 aka MULTI 8 (December 1977)
TMC1081NL - Panasonic JE-1604U (December 1981)

Reverse-engineering of Single-chip Calculator Circuits


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If you have additions to the above article please email:

Joerg Woerner, September 21, 2022. No reprints without written permission.