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The TA_PROG_SFP pin of the LS1046A is always connected to a 1.8V power supply

Hello,

I‘m using LS1046A.

From the checklist, I learned that 'Should only be supplied 1.8 V during secure boot programming. For normal operation, this pin needs to be pulled down through a resistor.'

But for some reason, the TA_PROG_SFP pin of the LS1046A is always connected to a 1.8V power supply in our design. May I ask what risks this design has?

Thank you!

Re: The TA_PROG_SFP pin of the LS1046A is always connected to a 1.8V power supply

Hello @KunChen 

Hope this post finds you well,

You are welcome, glad I could help.

If there’s anything else I can assist you with, please don’t hesitate to reach out. 

Have a great day!.

Best Regards,

Hector Villarruel S

Re: The TA_PROG_SFP pin of the LS1046A is always connected to a 1.8V power supply

Hi Hector,

Thank you for your reply.

Re: The TA_PROG_SFP pin of the LS1046A is always connected to a 1.8V power supply

Hello @KunChen 

Hope this post finds you well,

Regarding your questions,

The consequences of this behavior will be that the fuse  will blow, causing to overwrite the same information that it has previously and it will not be possible to program it again.

Please refer to the following information from the Section 4 Security fuse processor QorIQ LS1046A, LS1026A Data Sheet, Rev. 4, 06/2020.

To program SFP fuses, the user is required to supply 1.8 V to the TA_PROG_SFP pin per Power sequencing. TA_PROG_SFP should only be powered for the duration of the fuse
programming cycle, with a per device limit of six fuse programming cycles. All other
times, TA_PROG_SFP should be connected to GND. The sequencing requirements for
raising and lowering TA_PROG_SFP are shown in Figure 9. To ensure device reliability,
fuse programming must be performed within the recommended fuse programming
temperature range per Table 4.

Have a great day!

BR,

Hector Villarruel