These chips have never been made by UMC. As much as I know the W65C02S8P-10 reference was only made by WDC.

I found another thread here:

http://forum.6502.org/viewtopic.php?f=12&t=4277

This chip seems not to be compatible with the additional 65C02 opcodes

And here: http://www.vcfed.org/forum/showthrea...vs-65C02/page2

a user said that this chip is not working in his old apple IIe. So whatever it may be, it is not a real W65C02S8P-10-compatible chip

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