Here's that product, a sophisticated aircraft intercom, with about 900 parts in a box less than 4" x 5" x 2". At the top right you can see the CPU board, with an 8Kx8 EPROM on the solder side of the board. When we introduced it at a major airshow, one of the competitors was sure it was vaporware and the real work was being done by a big box under the counter. Our president picked it up and showed him that's all there was. He was speechless and his face turned several colors.

In the early stages of development, I considered several different microcontrollers for the job. Many had severe limitations for our application. One manufacturer actually told us that we basically were too small for them to be interested in our business. We settled on one of the Motorola 68HC11's. Unfortunately the version we needed with EEPROM and lots of EPROM was on allocation and not easy to buy. As it ended up, we just went back to a discrete 65c02 computer on its own board. Our cost for parts and labor was approximately what the HC11 was going to cost anyway-- it just took a little more room. (Again, the EPROM is on the back, making the board smaller.) Since then, it seems like Microchip PICs have practically taken over. The processor in them is really lowsy compared to the 65c02, but they have a lot of variations, features, I/O, built-in processor support like reset circuit and watchdog timer, etc., have good technical support with lots of ap. notes and free assembler etc., and are inexpensive and widely available, making them well suited for tiny jobs.