LPC1754 device serial number problem

[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 ?

[lpcware]

Content originally posted in LPCWare by Leji on Thu Apr 26 23:49:59 MST 2012
No ideas ? is noone using this feature ?

[lpcware]

Content originally posted in LPCWare by Leji on Tue Apr 03 02:37:58 MST 2012
I have the same issue with a batch of LPC1768FBD100.
Our first batch of ~1000pcs all have unique serial numbers, but on the new batches (~200pcs) IAP and Flash magic both only read 0xFF.

Does anyone know what's going wrong ? is that production issues or was the feature kicked out ?

[KingAndi]

Hallo!

We have now used about 20000 of this cpu's and we had (known from our test protocols) one CPU in the past with this problem. But today we have a couple of cpu's (about 5 pcs) which have exactly the same problem. Everything work's on the cpu but we are not sure what this means. We usually buy the cpu's from european dealers like arrow, but this cpu where bought during corona crisis directly from asia. So could it be possible that this is a "fake" or something similar. the cpu id is read correct and everything (we use) seems also to work correct...

Thank's a lot for your help, best regards

Andreas König from u::Lux