MOS Technologies apparently introduced the 6502 it although it was licensed to Rockwell and a couple of others. I also worked with the Motorola 6800, 6802 and we were about the first to use the CMOS 6805. I was working for Motorola at the time & we had pre-release samples. One challenge was when they changed the OR instruction from 2 clock cycles to 3 & didn't tell us. Suddenly our carefully timed loops just stopped working. It had a multiplexed address bus also so, although we had a very early HP logic analyser it wasn't usable on the samples. IIRC we were running at a clock speed of about 400kHz which was then divided by 4, The product was an early version POCSAG pager and we needed to run minimal clock speed to get the required battery life from as single AA carbon-zinc cell. Probably about 1980. RP On 18 January 2011 14:37, Harold Hallikainen wrote= : > Was that Motorola? I thought it was Mostek or something like that. I > remember they did the 6500 series (6502 processor, 6522 versatile > interface adapter, 6551 (I think) programmable uart, etc.). Motorola did > the 6800 series. I used the MC6802, which was a 6800 with internal clock > (just add a crystal) an 128 bytes of RAM. I think they had some designers > in common. I think I recall the 6800 was first, then some people went off > to do the 6502. The big difference I remember was the 6502 had two index > registers, while the 6800 had just one. I think the 6502 had 8 bit index > registers, while the 6800 had a 16 bit index register. I think the 6800 > had two accumulators and the 6502 had just one. The 6502 was used in the > Apple II, the VIC 20, Commodore 64, etc. > > Harold > > > FCC Rules Updated Daily at http://www.hallikainen.com - Advertising > opportunities available! > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .