UTEST memory area for factory data

[FelixR]

Hello there,

I am looking for a memory location on the S32K324 to store our factory data like the user hardware revision, softwar version, bootloader version and so on and I stumbled uppon the dcf_client_sdid0-15 entries in the UTEST Memory area and the DCF Clients sheet which apparently are made for that. But I am a bit confused about this Memory since the processor uses this area for some setups during boot as far as I did understand it. So I was wondering if this is even the right place to store my factory data?

regards,
Felix.

[petervlna]

Hello,

You can store your factory data in the following location:

The first 2 marked locations are made for that purpose.

In case you require more space you can also use DCF records space, but you must pay attention here to not overwrite DCFs.
In such case it is best to add it after stop record which is represented here by 0xFFFF_FFFF. I would do this only once DCFs are finalized and no more will be added. Also I will leave a enough space in case some will be added in future.

Best regards,

Peter

[FelixR]

Ah I see. One last quick question. I read in the reference manual that the UTEST area is OTP but it is a bit ambiguous "when" it is OTP. The reference manual says that "the UTest NVM sector is an OTP sector (assuming Test mode disable seal is written)". Does that mean that until I write the Test mode disable seal I can write multiple times inside my UTest Area, probably over my planned factory data just in case I write it wrongly?

[petervlna · Accepted solution]

Hello,

No. You cant rewrite data in OTP as customer.

The UTEST flash is made OTP via burning out TEST mode fuse in NXP factory.

There is no reverse possibility. It is permanent.

You simply tune the OTP in your development, which will maybe require several chips to be used for that purpose. But for factory production you will go with only one config as majority of customers.

Best regards,

Peter