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Datamath Calculator Museum TMS0500 8-Channel Serial Data Recorder 128-Bit Module

Date of introduction:  January 15, 2024 Display technology:  
New price:  $1,049.95 (2022 = $169.95 in 1974) Display size:  
Size:  3.2" x 4.8" x 0.8"
 81 x 122 x 20 mm3
   
Weight:  2.7 ounces, 65 grams Serial No:  0001
Batteries:   Date of manufacture:  mth 01 year 2024
AC-Adapter:  DC 5V Origin of manufacture:  USA
Precision:   Integrated circuits:  16*SN74HC595
Memories:  128 Bit Shift Register Displays:  
Program steps:   Courtesy of:  Joerg Woerner

The TMS0500 8-Channel Serial Data Recorder 128-Bit Module is part of the modular DCM-0500 (Platform) to allow Reverse-engineering of Calculators based on the TMS0500 Building Blocks for Scientific and Programmable Calculators and Recording of ROM Images of the Integrated Circuits (ICs) used with these calculators and connects to the East-Port of the TMS0500 ROM Platform.

The TMS0500 8-Channel Serial Data Recorder 128-Bit Module is basically and arrangement of eight 16-bit Serial-to-Parallel Shift Registers, for the TMS0500 Building Blocks only six channels are used:

Channel 1: EXT Signal
Channel 2: IRG Signal
Channel 3: not used
Channel 4: not used
Channel 5: I/O 1 Signal
Channel 6: I/O 2 Signal
Channel 7: I/O 4 Signal
Channel 8: I/O 8 Signal

While the TMS0500 Building Blocks uses a digit-serial architecture representing numbers in 16*4 bits are other calculator architectures using different approaches, Hewlett-Packard decided for example with its HP-35 with for a bit-serial architecture representing numbers in 56 bits. The configuration of the Shift Registers provided with one TMS0500 8-Channel Serial Data Recorder 128-Bit Module can be configured with a patch field into eight 16-Bit channels, four 32-Bit channels, two 64-bit channels or one 128-Bit channel. For more demanding applications up to eight of the Modules can be stacked in a piggy-back manner for a combined 1024-Bit Module thanks to an integrated 8-Module Decoder.

In the process of Reverse-engineering of Calculators the TMS0500 Building Blocks two modules are connected to the East-Port of the TMS0500 ROM Platform:

Bottom: TMS0500 8-Channel Serial Data Recorder 128-Bit Module
Top: TMS0500 8-Channel Serial Data Recorder with Arduino DUE

The first module is used to de-serialize the relevant signals from the calculator under investigation into parallel 16-bit words and makes them available to the Arduino DUE of the second module running "TMS0500 DATA Recorder" Software to capture and log the information from the IRG and EXT signals and the I/O Bus and listing them it in a human readable form in a terminal window.

In the process of Recoding of ROM Images of the various ROM Chips of the TMS0500 Building Blocks the same configuration is extended by the TMC0501/TMC0501E Emulator connected to the West-Port of the TMS0500 ROM Platform running to stimulate the ROMs and Arduino DUE is running software to to convert the ROM responses into actual ROM listing.

Other features of the TMS0500 8-Channel Serial Data Recorder 128-Bit Module include an Overflow-Latch to signal with a red LED that the de-serialized data wasn't retrieved in a timely manner, a red [RESET] push button clears the Latch accordingly.


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

Joerg Woerner, January 7, 2024. No reprints without written permission.