Sherwood Micro CPU/100

Ethan Dicks wrote: It was fun to play with for a bit once they were working, of course you can set in whatever four-letter word for a station you wish. The alphanumeric display uses LED dot-matrix units, so it's a much nicer display than the usual 7-segment types. There's also a slide-rule tuning display of a row of LEDs to keep those who couldn't make the transition to pure digital in one jump happy [*]. Capacitive touch-sensitive buttons for presets and scanning using 555 timers as the sensors, along with an optical rotary tuning knob. The 1802 handles all this and calculates the factor to load into the PLL divider for the synthesised tuning. Various other technical features. It's something of a tour-de-force of 70's technology/electronics design, although the actual physical construction leaves something to be desired, (IMHO). The downside is that all that stored state (presets, frequencies, call letters) required batteries to hold the CMOS memory, and of course they used NiCd's, mounted on the main power supply board. And of course they leak. The units I worked on required significant rebuilding. [*] I remember the consternation the transition from analog to digital clocks caused in the mid-70s. Many people seemed to have difficulty with it and were somehow concerned that it might 'change our perception of time'.