restart pmic

[liyw]

Test Request and Observation:

I have a test request where I need to frequently restart the MCU (Microcontroller Unit).

During the testing process, I observed that the PMIC (Power Management Integrated Circuit) FS84 entered the DEEP-FS mode. This may be due to frequent feeding of the Watchdog Timer (WD) trigger.

Issue Encountered:

When I restart the MCU, the PMIC does not restart. Therefore, I hope to restart the MCU by first restarting the PMIC.

Question:

However, I don't know how to restart the PMIC FS84 using an SPI (Serial Peripheral Interface) command.

[liyw]

Thank you to Tomas,

The FLT_ERR_CNT reached its limit due to an incorrect watchdog (WD) refresh. Here's how I plan to address it:

1.When the MCU starts, I will check if the PMIC has initialized. If it has, I will not feed the WD until a close window time. If the PMIC has not initialized, I will feed the WD immediately.
2.When I restart the MCU, I will check if the watchdog refresh time exceeds the close window. If it does, I will refresh the WD immediately.
3.By using this method, I will resolve the issue of incorrect WD refresh errors.

[liyw]

Hi,

   TomasVaverka, Thank you for your answer.
   Via testing, I know the cause of entered DEEP-FS mode is a bad refresh of WD. However, resetting the MCU is my purpose, so I don't want the PMIC to enter DEEP-FS mode.
1. how do I feed the watchdog? Currently, I feed the watchdog when the MCU starts.
2.how do I stop PMIC fault detection?

[TomasVaverka]

Hi,

BRs, Tomas

[liyw]

hi,

    Tomas,

    When I want to restart the MCU, the PMIC has entered the normal phase, not INIT_FS, and I cannot wait too long for the next good watchdog (WD) reset.

     So I cannot disable the watchdog timer. I hope to reset the MCU without triggering any errors. How should I do this?

[quangvuanh]

Hi Liyw, are you using SBC FS8X software driver provided by NXP?

[liyw]

yes

[quangvuanh]

Hi, I am not sure what software version that you are using with the snippet you provided.
By the way, based on the information you shared I think you should force the device into INIT_FS on every reset event, by setting this bit GOTO_INITFS in FS_SAFE_IOs register.

Can you please also let me know what version of the driver that you are using?

[TomasVaverka]

Hi,

Here is a summary when the FS84 enters the DEEP-FS mode.

In your case I suppose that the FLT_ERR_CNT reached its limit due to incorrect WD refresh. 

The following methods can be used to exit the DEEP-FS mode.

BRs, Tomas