Field-Modifiable Electronic Devices
Original Publication Date: 1985-May-01
Included in the Prior Art Database: 2005-Feb-18
Mechanical devices, for example, keyboards and vehicle motors, now are often controlled by an associated microprocessor. In turn, the functioning of the microprocessor is controlled by fixed data in a read-only memory (ROM). The control of the device is made modifiable at any stage after initial manufacture by employing a conventional electrically programmable read-only memory (EPROM) as the microprocessor control ROM. Such EPROMs typically are erased by ultraviolet light and then accept signals which revise their content. For this purpose, the passivation coating protecting the EPROM is FLUORAD* brand Conformal Coating FC-725, which transmits the ultraviolet light well. The drawing is suggestive of the mounting of the control circuitry.