stepping machanism of Apple Disk ][ drive (was Re: Heatkit 51 /4 - test-drb@ccmp.vtda.org

14 Apr 1999

...
    Then there was the Tektronix 'almost 6800'
used in the 4052, etc. It was
 a board of 2901's, etc and ran an instruction set that was almost upwards
 compatible with the 6800 used in the 4051 (IIRC the DAA instruction was 
 The moto 6800 was protoed using 2901s. It would only need two. 
 The Tektronix used 4 2901's and was actually a 16 bit processor (for
 address calculations, etc). Just that user data was only calculated using
 2 of the chips ;-) 
Hey, Tony, why the winking smiley?  That's no joke, it's really true!  Four
2901s and a lovely 16bit architecture, and then they go and implement a 6800 on
it.  :-( :-( :-(

Philip.