DATAMATH CALCULATOR MUSEUM
|Date of introduction:||1979||Display technology:||Fluorescent|
|New price:||DM 29.00||Display size:||8|
|Size:|| 5.6" x 3.0" x 0.8"
142 x 75 x 20 mm3
|Weight:||3.9 ounces, 110 grams||Serial No:||G 15240|
|Batteries:||2*AA||Date of manufacture:||year 1979|
|AC-Adapter:|| BH-115 (110V) or
|Origin of manufacture:||Taiwan|
|Precision:||8||Integrated circuits:||TMS1045 (MT7919)|
|Program steps:||Courtesy of:||Joerg Woerner|
This Toshiba BC-8112SL "Enhanced Basic" calculator followed the otherwise identical BC-8112SR and shares its internal design with the BC-8018B "Basic" and BC-8111B "Basic with Memory" calculators. The rather unusual approach to use identical electronics for three calculators with a quite different feature set was made possible with Texas Instruments' introduction of the cost-effective TMS1040 Product Family based on the TMS1070 "computer-on-a-chip" introduced in 1974 with the original TMS1000. But we have to credit Canon releasing the full potential of the TMS1040 with its "Almost Scientific" F-31 calculator in 1977.
Comparing the functionality of the three Toshiba calculators and the Canon F-31 demonstrates the bandwidth of products made possible with the TMS1045 single-chip calculator circuit:
the featured BC-8112SL calculator manufactured in 1979 by
Zeny Corporation in Taiwan
reveals a very cost effective design using a single-sided printed circuit board
(PCB) centered around a TMS1045 single-chip calculator circuit connected to a 9-digit
Vacuum Fluorescent Display (VFD), a keyboard assembly and powered by 2 AA-sized
While the earlier TMS1070 can directly interface with low-voltage VFD up to 35 Volts does it still need external resistors and a zener diode to bias the anodes and grids of the display with respect to the filament. The TMS1040 added an extra VPP pin to connect a negative 30 Volts bias voltage for its modified output drivers. With the TMS1070 featuring 11 R Outputs for the Digits, 8 O Outputs for the Segments and 4 K Inputs for the Keyboard, reduced the TMS1040 the number of R Outputs to 9, consequently are all known TMS1040 calculator designs using a 9-digit VF Display.
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© Joerg Woerner, October 26, 2002. No reprints without written permission.