Erik I have Phillips AN461 of 2001 oct 11. In it on page 9 is a schematic for the P89c51rd + PLCC that shows pin 32 PSEN grounded for ISP.
I merely request that when naming pins by number he includes the package or - much simpler - say PSEN. PSEN is not the same pin number in all packages.
but no "ls" parts are shown is it possible that he has a different AN461? Terry
Possible, yes the release of the doc is 11. Likely, no I have followed this doc through many iterations(may, of course have missed a few) but never seen a LS part in that appnote.

Erik