I purchased some 65C02's on eBay in June to use on
my V1 6502 CPU board. While my wire-wrap CPU board used a 'C02'
(GTE 65SC102-2 to be a little more definitive) I had never
written any code that used the 'C02' added opcodes, addressing
modes, or other features. My DOS/65 code uses strictly NMOS 6502
opcodes etc.
I wrote a short utility that used BRA instead of JMPs and
in one spot used an INC A opcode. The utility would not work
leading me to question whether I had the residual brain cells
to have fun with computers. I changed the code to remove any
'C02' opcodes etc. and the utility worked fine. I was now
suspicious.
I then used the few lines of code that perform BCD
arithmetic as the NMOS 6502s do not correctly handle the flags
when doing BCD arithmetic. The CMOS versions do correctly set
the flags. This test clearly indicated that what was labeled a
65C02 (specifics in a minute) was not a 65C02 but was an NMOS
6502.
Bottom line - the ICs appear to be intentionally
mislabeled. So if you see an eBay add for a 65C02 with the
following lines and with the Rockwell logo to the right of the
first three lines be careful.
R65C02P4
11450-13
MEXICO
0815 S11468-4
I did a quick eBay check and more than seller in China had
IC pictures with this marking. Some may be correct but I
suspect many are not.
By the way, when I pulled the new 6502 V1 board and put my
30+ year old wire wrap board in my system to run the same
tests on the GTE IC, it refused to start. I guess I really do
need the V1 6502 CPU!
Rich Leary