Texas Instruments Constant Memory Module (EVT 1)

Date of introduction:  Never
 (Announced: May 1982)
Display technology:  
New price:  MSRP: $50.00 Display size:  
Size:  1.3" x 1.25" x 0.55"
 33 x 32 x 14 mm3
Weight:  0.45 ounces, 13 grams Serial No:  
Batteries:  LF-1/2W Date of manufacture:  wk 17 year 1982
AC-Adapter:   Origin of manufacture:  USA (ATA)
Precision:   Integrated circuits:  2*TP0531
Memories:  148-0    
Program steps:  0-1184 Courtesy of:  Joerg Woerner

The Constant Memory Module was developed by Texas Instruments for its TI-88 Programmable calculator system and available as an option the calculator.

This Constant Memory Module was included with an early TI-88 EVT (Engineering Validation Test 1) and sports a a transparent housing to verify mechanical fit of the integrated backup battery.

Dismantling a Constant Memory Module included with a later TI-88 PVT (Production Validation Test) and manufactured in September 1982 by Texas Instruments in their Abilene, Texas facility, reveals a printed circuit board (PCB) to accommodate up to two TP0531/TP0532 Memory Chips. The PCB is populated with two TP0531 Read/WriteMemories (RAMs) with a capacity of 4,800 Bits or 600 Bytes, each and a Sanyo 3 Volts lithium battery from the type LF-1/2W with 24.0 mm diameter and a thickness of 3.0 mm - matching today's CR2430 cells.



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If you have additions to the above article please email:

Joerg Woerner, October 12, 2019. No reprints without written permission.