Solitron Devices, Inc. is an American semiconductor manufacturer.
In 1971, Unisem advertised model UA3533, a single-chip keyboard encoder with 4608 bits of look-up table ROM capacity. The next year, it was advertised as a Solitron Devices product, following the 1971 acquisition of United Aircraft’s Unisem semiconductor division by Solitron Devices.
The product was specified as follows:
- Static keyboard encoder
- 128 coded key capability
- 4 modes
- 512 unique 9 bit codes
- Keybounce effects eliminated by internal strobe control
- Two key rollover
- Single switch closure addressing
- Shift lock with indicator capability
- Ignores false pulses up to 4 µs
As a static encoder, this will not be matrix scan. Consequently, this may be a two-of-N encoder, requiring switches with dual isolated outputs. There seems to be no other documented mention of this chip, although it does appear on surplus part sites.
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