eFuse lock bits with random setting

jschoen — Thu, 27 Mar 2014 16:48:56 GMT

We are seeing an occasional issue where efuse address 0, OTP Bank0 Word0 (Lock controls), i.e., shadow register OCOTP_LOCK, does not contain the factory default value of 0x20220002. Maybe 2 or 3 out of 100 processors will have other random bits set causing, for example the Ethernet MAC address to be locked and not writable. We have seen 0x20220003, 0x20220012, 0x 20220202.

We are reading and writing the fuses through a version of u-boot that is loaded over USB during factory test. Thinking that u-boot’s efuse write function may have a bug, we added code to read the lock fuse before doing any fuse writes and we are reading bit errors there too making us think the processors may be coming from Freescale with random lock bits set in error.

Has anyone else seen anything like this problem before?

Re: eFuse lock bits with random setting

jschoen — Thu, 27 Mar 2014 16:50:19 GMT

This is for i.MX6Q

Re: eFuse lock bits with random setting

lily_zhang — Wed, 09 Apr 2014 05:45:36 GMT

hello,

Can you please provide more details?

1. Which U-boot version you are using?

2. What's your part numbers you are using?

3. What's your detailed steps to do fuse blown/read testing? Do you have full memory fuse dump information?

i.MX ProcessorsのトピックeFuse lock bits with random setting

eFuse lock bits with random setting

Re: eFuse lock bits with random setting

Re: eFuse lock bits with random setting