Hi,

During granting my wife's wish to remove dust throughout the flat, I found that I have two Commodore 16s in a very bad condition but with CPU in them, and socketed ones. I've totally forgotten about them during the years it seems ... Since I am about to build some minimal 6502-like system and I don't have CMOS 65C02, only 6502 from UMC (named UM6502) I thought that Commodore 16's CPU would be still a better choice than UM6502, it is: 8501. For example (as an 6510 derivant) the bus can be tri-stated, and 6 bit on-CPU I/O port can be used. However at the point I've stucked because of lack of enough information.

What 8501 is for real? According to google, 8500 was a HMOS version of 6510, and nothing more. Then it says, 8501/7501 was used in Commodore 16 & Plus-4. However there is no information what is the difference between 8501 and 8500, or what is 7501 compared to 8500 (and maybe 7500, 6510?).

Then as far as I know there is 8502 which is 2MHz-capable version of 8501 (?) and was used in Commodore 128. So I guessed 8501 is 1MHz then. But it's odd, as even C16 used clock at 1.76MHz (not always, only during the horizontal&vertical retrace?). So then 8501 is not a 2MHz chip (as 8502 is that) but still it does know more than 1MHz officially if it's used in production for this ...

I couldn't find official data sheets on these CPUs, so I have not got so much idea what 8501 is for real (since I have those in my C16s), what clock are they designed for, and what are the differences compared to 6510 (if any), or does the HMOS technology creates any problem for me to replace "plain" NMOS?