[comp.sys.atari.8bit] 1200xl portb

Cothrell@DOCKMASTER.ARPA (09/07/87)

I would like to know what the pinout of the 1200xl's port b is.  also,
which pin on the 6520 corresponds to bit 0 (I assume the rest are meerly
increments of bin and bit).  Also, there have been some rumors on
occasion that the CPU in the Atari 8 bitters is a custom CPU with a 6502
instruction set.  Is this true?  If so, what changes were made?  I have
a 65C802 CPU (16 bit, 6502 pin compatible) that I would like to drop
into my 1200 or 130XE.  A friend has done this with a Vic-20 (no laughs
please) and had no problems...except his games sped up.  Comments and
suggestions are welcome.

Cothrell -at dockmeer)