Mystery Uncovered: National Winbond Nuvoton PC97551
So I bought some chips on eBay, they arrived, and are New Old Stock, made in 2004, really fairly recent. I have a datasheet for them that is marked Winbond which I found rather strange, since the chips, as you can see are marked National. This in itself isn’t super unusual. Occasionally a smaller company will use a larger companies markings to get design wins. The larger company acts in essance like a co-signer, validating and approving of the design.
National PC97551
Winbond isn’t small though, and the datasheet was marked 2006. A quick look on Winbond’s site shows no info on this chip. Turns out Winbond spun off their controller business to a company called Nuvoton. And how did Winbond get the desgin? Yup, National sold off their Super I/O and embedded controller division to Winbond in 2005.
And it is of course a processor, in this case a 16bit RISC processor running at 20MHz based on the (formerly) National CompactRISC architecture.
