Monsanto MDA111 Display Module  
Written by AnubisTTP on 2008-04-16  


A rare part indeed, the MDA111 is a first-generation fully alphanumeric LED display module. The heart of the MDA111 is the Mostek 2302, a six-bit character generator ROM in which all of the bitmaps for the ASCII characters have been encoded. The 2302 drives a Monsanto MAN-2 5x7 bitmapped LED display, which is generally considered to be the first 5x7 LED display made available to the public. A constellation of transistors interfaces the MAN-2 to the 2302, and several other integrated circuits provide clock and buffering logic.

The market viability of such a complex device was short lived; within a few years displays like the HPDL-1414 became available, in which the complex driver electronics of the MDA111 have been condensed into a single die and incorporated into the diode package itself.


Monsanto MDA111 LED Display Driver
Monsanto MDA111 display drive module with ">" character selected.

Mostek MK2302 character generator
The brains of the MDA111, a Mostek MK 2302 6-bit character generator.

Monsanto MAN2 LED Display Driver
The MDA111 mounts a MAN-2, the first model of 5x7 bitmapped LED display, for character indication.

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