Texas Instruments TMS1100 Product Family


The TMS1100 Microcomputer introduced in June 1976 doubled both the ROM Size and RAM Size of the original TMS1000 Microcomputer and kept all other parameters identical for an easy upgrade of existing designs. As of today we know only two Texas Instruments calculators using the TMS1100, the failed SR-40 Prototype and the short-lived TI-5050M. Nevertheless was the TMS1100 a success for Texas Instruments, powering everything from electronic games to microwave ovens and even the World's first Computer Radio Scanner used these chips.

Family Members and Applications

Type Calculator Application Comments
TMS1111 SR-40 Scientific Prototype
TMS1115 TI-5050M Small Printing  
TMS1116 Regency ACT-T16K Radio Scanner  

Note: Learn more about the MOS Numbering System used by Texas Instruments' early MOS Chips.


  Description Comments
Architecture Single-chip Calculator First Generation Digit Processor
Category Digit Processor 4-bit digits
Related TMS1000 Portfolio  
ROM Size 16,384 Bits 2,048 Words * 8 Bits
RAM Size 512 Bits 8 Registers * 16 Digits
Outputs 11 Digits, 8 Segments External Digit Drivers
Inputs 4 Keyboard
0 Miscellaneous
Digit to Keyboard Scan-Matrix

DCM-50A Platform Compatibility

The Datamath Calculator Museum DCM-50A (Platform) supports TMS1100 chips directly with the TMS1000 Textool Test Socket set to DCM-50A (TMS1000) mode. Both Characterization of TMS1100 Calculator Circuits and Reverse-engineering of TMS1100 Calculator Circuits is supported by the DCM-50A (TMS1000)).

Technical Specifications

Parameter Min Typ Max Unit Comments
VSS   0   V   
VDD -14 -15 -17.5 V 15V Series
VDD -7.5 -9 -10 V 9V Series
IDD   4.5 10 mA 300 kHz, -15V
VOUT 0.3   VDD V Output Voltage
Ext. CK  100   400 kHz Level between VSS and VDD
Int. CK  250 300 350 kHz Rext= 50 kOhm, Cext= 47 pF


The original TMS1100 was manufactured in a 8 um metal gate PMOS process (metal width = 0.30 mil / 8.0 um, metal spacing = 0.35 mil / 9.0 um, diffusion width = 0.25 mil / 6.0 um, diffusion spacing = 0.35 mil / 9.0 um).


The TMS1100 is using in TI's calculator applications a standard 0.6 wide 28-pin DIP (Dual In-line Package with a 0.1 / 2.54 mm lead pitch).

Pin Configuration

Pin IO Function Pin IO Function
1 O R8 Output 28 O R7 Output
2 O R9 Output 27 O R6 Output
3 O R10 Output 26 O R5 Output
4 V Negative Voltage VDD 25 O R4 Output
5 I K1 Input 24 O R3 Output
6 I K2 Input 23 O R2 Output
7 I K4 Input 22 O R1 Output
8 I K8 Input 21 O R0 Output
9 I INIT (Reset) 20 V Common Voltage VSS
10 O O7 Output 19 I OSC2 (Ext. CLK = VSS)
11 O O6 Output  18 I OSC1 (Cext, Rext) or Ext
12 O O5 Output 17 O O0 Output
13 O O4 Output 16 O O1 Output
14 O O3 Output 15 O O2 Output

Keyboard Scan-Matrix




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If you have additions to the above datasheet please email:

Joerg Woerner, December 3, 2023. No reprints without written permission.