LPC1754 device serial number problem

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by stefko on Mon Dec 05 12:40:46 MST 2011
Recently we purchased a new batch of LPC1754FBD80, some 20pcs.

They seem to work fine but when I read the device serial number(signature) they give 0xFFFFFFFF (times 4).

I read this data using both my firmware (through IAP calls) or the FlashMagic.

When call IAP function the result code is 0x00 (OK), but the data is all FFs.

I get correct results when reading part identification number (0x2501 1722) and the boot code version (4.2), again the same data with my FW and the FlashMagic.

I have 2 chips from another batch which behave correctly and according to the datasheet report nice device signature (perhaps unique), the same boot code version and part ID. My plans are actually to use the LPC1754 device SN as part of the USB  device instance ID (along with the VID and PID) .

Has anybody seen this problem ? Any advice ?