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Sample Project 1

Motorola MC145428 Replacement

The Problem:

Motorola has discontinued the MC145428 Data Terminal Interface. This chip converts serial data for encoding in a synchronous serial stream. The client did not want to redesign their system. In addition they did not want to have to change their software as that would require an entire retest cycle.

The solution:

I designed a small PCB that plugged into the socket. This board used a Microchip PIC processor to emulate the chip via software. The prototype is shown below:


The large picture shows the client's board with the adapter board. On top of the adapter board is an emulator for for the PIC processor. The right two pictures show the finished board (quarter shown for size.) The small connector on the top of the board is for programming and debugging and would not be used in a production version.

The entire project took only a few days to design, build and test. In less than a week I delivered the prototype with the software tested and running. It worked fine in the client's system. I provided the schematic and software to the client. They were capable of laying out a production PCB and building and testing the boards.

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