OTP fuses for temperature grade -- MX6D

[simonecumar]

Hi all,
 I have a board with a MX6D derived work. Looking at the fuses, I see no differences between Consumer and Industrial grade chips, in particular:

cat /sys/fsl_otp/HW_OCOTP_MEM0
0x0

Isn't this supposed to be flashed by NXP during manufacturing or am I doing anything wrong?

[Harvey021]

Hi @simonecumar 

There exists more description on AN4581 as below.

3.3.2.2. Option 2 – Set RNG trim in fuse
The Fuse setting is essentially a delay. Increasing the value increases boot time. The recommended safe value for ensuring the self-test passes is 0x10. Smaller values may work on some parts, but not all. The delay required to pass the test could also vary based on temperature.
• Program the RNG Trim fuse value using the fuse command available in i.MX U-Boot.
— On i.MX 6 Series 0x480[23:16]:
fuse prog 1 0 0x00100000
— On i.MX 7S and i.MX 7D 0x4C0[15:8]:
fuse prog 3 0 0x00001000

Best regards

Harvey

[simonecumar]

Hi@Harvey021 , thanks for the reply.
I understand that you are saying it contains another value. But my goal is to understand if the chip is industrial grade or commercial grade. As stated below, I have taken parts of the reference manual IMX6DQRM that states the temperature grade located at offset 0x480[7:6] ( https://community.nxp.com/t5/i-MX-Processors/OTP-fuses-for-temperature-grade-MX6D/m-p/1501835/highli... )

Is this piece of information correct? If not, where is the temperature grade located?

Best regards,
 Simone

[Harvey021]

Hi @simonecumar 

Based on the value with 0x0 that you run cat, It is  00-Commercial.

And you can refer to datasheet with your part No for details.

Best regards

Harvey

[simonecumar]

Thanks again @Harvey021 
Based on the part number MSCMMX6DZCK08AB1G0AA, it should be industrial.

[Harvey021]

Hi @simonecumar 

HW_OCOTP_MEM0 is used to access RNG_TRIM. which should be turned on by your side. There is more details related to RNG_TRIM in AN4581.

Best regards

Harvey

[simonecumar]

Thanks for the reply.
What I found in the fusemap is that address 0x480 should contains the temperature grade



this value should be loaded in the HW_OCOTP_MEM0 since it has offset 0x480.



If HW_OCOTP_MEM0 contains RNG_TRIM as you said, then where is the temperature grade located?