Additional Pictures 


Close-up view of the TMC1993 single-chip calculator circuit used with the Little Professor (1980).
PMOS Technology, 28-pin SPDIP 4-bit Microcontroller, 1,024*8 Bits Instruction ROM, 64*4 Bits Data RAM.

Die Photo (after acid) of the TMC1990/TMC1993 courtesy of Sean Riddle.

If you have additions to the above article please email:

Joerg Woerner, May 3, 2021. No reprints without written permission.