UCD90320: Clarification on 0xDB Command Usage for UCD9032 Remote Upgrade

Hi Yihe,

We would like to ensure that the correct sequence is followed during the reset process after the upgrade. Since the 0xDB command for a soft reset does not support maintaining this sequence, could you please suggest an alternative method that would allow the sequence to be followed?

Best regards,
Elsa

Hi Yihe,

We need clarification on how GPI Faults interact with the "Faults shutdown other rails" feature in Fusion Digital Designer.

Setup:

• One EN pin is connected to a GPIO
• GPIO is configured as:
  • GPI
  • GPI Fault enabled
  • Active High polarity
• EN default state is Active High
• Writing 0 to this pin is done via PMBus GPIO commands (0xFA GPIO_SELECT,0xFB GPIO_CONFIG).
• In GPI Fault Responses, when this GPI is driven low (fault condition), only some rails are configured to shut down
• Separately, the system is configured such that if any rail faults, all rails should shut down

Questions:

1. When we deliberately write 0 to the EN pin and trigger a GPI fault, how does the controller classify this event?
   1. Is it treated as a rail monitoring fault (OV/UV/OC/OT/TON_MAX)?
   2. Is it treated as a PMBus user‑triggered fault?
   3. Or is it treated as a GPI‑originated fault, independent of rail monitoring faults?
2. When the GPI fault shuts down the selected rails, will this action cause a cascading shutdown of all rails because the system is configured to shut down all rails when any rail faults?
   
   

Best Regards,
Elsa Eldhose