LPC1752 UID not in early chips?

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by mozmck on Mon Jan 21 14:35:08 MST 2013
I am reading the UID using IAP in LPC1752 chips, and it seems that the newer chips work fine, but a couple of older chips just return FFFFFFFF for 3 of the numbers and 0 for the first one.  The parts are all revision A, and the date code on the chips that return a valid number is 1215, the older ones that don't work are 1135.

Did the older chips not have a UID, or is there a different way to access it?  I can't find anything that says so.