topic Re: OTP/eFuse vs Shadow ... I'm confused... in i.MX RT Crossover MCUs

OTP/eFuse vs Shadow ... I'm confused...

EdSutter — Tue, 21 Apr 2020 22:04:37 GMT

I'm confused regarding the OCOTP...

Couple of questions:
1.Referring to the IMXRT1060 Reference Manual (12/2019), it talks about the OTP space
(using eFuse and OTP interchangeably). The OTP space has shadow registers that are shown
in figure 23-2; with most of the space labled "Reserved". I assume this represents the 2kbit
of OTP space. Section "23.4.1 Operation" has sections that are titled "Fuse and Shadow
Register Read" and "Fuse and Shadow Register Write" but aren't they really just discussing
the "Fuse" access protocol? Aren't the shadow registers just accessed through the OCOTP
registers directly?
For example, if I want to access the actual OTP value for MAC0 I would follow that
protocol (using OCOTP->CTRL and others) to read the OTP.
But if I wanted to read the shadow copy, I would just read OCOTP->MAC0.
Is that correct?

2. The security section also talks about other OCOTP reqisters, like the Unique ID etc...
Where are they?

3. One of the features of the OCOTP is "generation of STICKY_REG". I know what a "sticky"

bit usually refers to, but there is no other mention of STICKY_REG in the manual. What is it?

Thanks,
Desperately trying to get up to speed on this processor...
Ed

Re: OTP/eFuse vs Shadow ... I'm confused...

jeremyzhou — Wed, 22 Apr 2020 07:00:25 GMT

Hi Ed Sutter,

Thank you for your interest in NXP Semiconductor products and
for the opportunity to serve you.
1) Is that correct?
-- Yes.
2) Please refer to the security RM to learn information about the last two questions.

Have a great day,
TIC

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Re: OTP/eFuse vs Shadow ... I'm confused...

EdSutter — Wed, 22 Apr 2020 11:36:02 GMT

Thanks; but that link takes me to an "Update Account Information" page that seems to just die.

It asks me to update my account for some reason (I'm already logged in); then I click the "I'm not a robot" (captcha) box and then submit. A minute later the the captcha box un-checks itself and says: Verification expired. Check the box again". I did that several times in what appears to be an endless loop. Any other way I can get that RM?

Re: OTP/eFuse vs Shadow ... I'm confused...

EdSutter — Wed, 22 Apr 2020 15:32:15 GMT

Jeremy,

I see now that the document is restricted. I'm working with my FAE to get a copy of this...

Thanks,