On Wednesday (03/23/2022 at 04:18PM +0100), Christian Corti via cctalk wrote: > On Wed, 23 Mar 2022, Chris Elmquist wrote: > > More interesting. If the programming algorithms remained the same then I > > guess it is just an issue for the programming system-- when it auto-IDs, > > it should display (and allow!) 27C256A instead of 27C256. > > > > I guess the next question is whether the programming algorithms really > > are the same between the 8CH and the 8DH variants?? > > > > My limited testing suggests they are at least compatible since my 8DH > > appears to be working when programmed as an 8CH. > > I didn't even know that primitive EPROMs have device IDs... > Without looking for a data book, how is the ID mechanism implemented?
Intel called it "Intelligent Identifier(tm) Mode". From page 5-43 of my 1991 Intel Memory Products book, for the 27256, You put Vh (+12V) on address A9 and then, with A0=0, you will read out the manufacturer ID with A0=1, you will read out the device ID Chris -- Chris Elmquist
