Cleaning house since movement therein has become
difficult and while
trashing out an old piece of equipment came across a SBC consisting of
a Rockwell 6501 that ran a credit card reader.
Note that the Rockwell R6501Q is *not* a second-source of the
MOS Technology MCS6501 (nor was CRC suggesting that it was).
The R6501Q is a member of Rockwell's microcontroller family, which use
a 6502 core with on-board memory and I/O, similar to the 8035/8048 family.
I don't recall whether the R6501Q contained masked ROM, but it did have
192 bytes of SRAM.
One of my friends used to make SBCs using the R6511Q, which had
fancier on-chip I/O, timers, etc.
I'm still looking for an R65C29, which was a dual-core 6502. There
was a datasheet, but I'm not sure they actually made the part. The
single-chip microcontroller version was the R65C00/21.