|Re: HP35s Internal Investigations - new processor?|
Message #4 Posted by Eric Smith on 8 Mar 2012, 2:33 a.m.,
in response to message #3 by uhmgawa
The part that was pin-compatible with the Motorola MC6800 was the MCS6501. I've got a computer using an MCS6501 from the late but not much lamented company "the Digital Group". The part number for a plastic-packaged part would have used the prefix "MPS", but I haven't seen any evidence that it actually shipped. The more well-known part was originally designated the MCS6502 or MPS6502.
The original second-source vendors, Synertek and Rockwell, used different prefixes and suffixes. Synertek used "SYC", "SYD", and "SYP" for ceramic, CERDIP, and pastic, respectively. Rockwell used an "R" prefix, with a "C" suffix for ceramic and "P" for plastic. Both Synertek and Rockwell often omitted the letter denoting the package variant from the actual labelling printed on the part.
The more interesting story about the MC6809 (IMHO) concerns Hitachi's CMOS version. Hitachi was a licensed second-source for many Motorola parts, and developed CMOS versions of some of them, generally replacing the "68" with "63" to designate CMOS. In the case of the MC6809, they also decided to extend the architecture, adding more registers, and even a few 32-bit operations. Reportedly Motorola was very unhappy about that, and somehow brought pressure to bear on Hitachi which resulted in the architectural extensions of the HD6309 not being described in the public documentation. It was only years later that the details were leaked to a Japanese magazine.