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Circuit Description

A demonstration of a 16-segment display. Unlike the well-known seven-segment displays, the multi-segment variants can display the numerical digits, all uppercase letters, and many symbols.

The simulation model is based on the Siemens DL-1414 integrated circuit, which combines an internal character decoder and driver transistors with the LEDs in a single package. Such displays were fashionable in the 1980's (my DL-1414 datasheet is from 1982), but have been replaced by Liquid-crystal displays since then. However, 16-segment alphanumeric displays (without integrated controller) are still available commercially as standard components, e.g. Kingbright PSA08 (from www.reichelt.de). Note that the displays actually use 17 LEDs, due to the extra LED for the decimal point.

While the simulation model provides eight input ports, the internal circuit only decodes the range 32 to 95 (00100000 .. 01011111) with the following mapping:

  0010 0000      space
  0010 0001    ' quote
  0010 0010    " double quote
  ...
  0010 0111    / slash

  0011 0000    0
  0011 0001    1
  ...
  0011 1001    9

  0011 1010    symbols
  ...
  0011 1111    ? questionmark

  0100 0000    @ at-sign
  0100 0001    A
  0100 0010    B
  ...
  0101 1010    Z

  0101 1011    [
  ...
  0101 1111    _ underscore