Cosmac

--- Philip Pemberton <philpem(a)dsl.pipex.com> wrote: Never thought of the origins, but that's an astute guess. I just figured it was a catchy name invented by marketing. Voyager I and II, and Galileo (a recycled Voyager spare). In addition to radiation resistance, the 1802 works down to 0 Hz - it can be statically clocked - a buddy of mine built an Elf in high-school and didn't own an oscilloscope - for debugging it, he used a debounced switch and an analog VOM. He followed along the timing diagram in the RCA docs and manually toggled it through the states (8 clocks per cycle, 2 or 3 cycles per instruction). Unlike lots of modern processors, you can have an arbitrary amount of time between clock ticks, providing for serious power savings when a spacecraft is in cruise-along-and-ignore-things-for-weeks mode. Just set an "alarm" to speed up the clock when an event comes in, or every so often, then conserve for the rest of the trip (the Voyager frame uses plutonium RTGs (radio-isotope thermal generators?) for power, so it's not like you save on the batteries, but the principle is the same - don't stress the equipment if you have nothing to do. The 1802 is one of my 3 favorite microprocessors. As everyone else has said, nice find. -ethan __________________________________________________ Do You Yahoo!? Yahoo! - Official partner of 2002 FIFA World Cup http://fifaworldcup.yahoo.com