i.MX6 WDOG Reset - Ethernet not working

[mahi]

Hi community,

we have a custom Boards with i.MX6 Dual and DualLite. The connection between WDOG1_OUT_N and i.MX6 Reset input is currently not assembled.

When doing a reboot using watchdog 1 ("Reset cause: WDOG"), Ethernet is not working (no packets are reiceived, but I can see data on the RGMII RX pins).

After connecting WDOG1_OUT_N and SRC_POR_B ("Reset cause: POR"), Ethernet works fine after issuing a reboot command.

We are using fsl release bsp 4.1.15-2.0.3.

Usually, I would expect an internal watchdog reset to be almost the same as a POR (except for reset reason).

Has anyone made the same experience?

Is there a way to improve/fix wdog reset?

Best regards

 Martin

[Yuri]

Hello,

  The watchdog internal reset is a WARM one. Generally it is highly recommended to remove

power for all components on the board in the event of a processor reset to avoid unpredictable

states.

Have a great day,

Yuri.

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[mahi]

Hello Yuri,

the only component that needs the "hard" reset is the i.MX6.

The aforementioned connection between WDOG1_OUT_N and i.MX6 Reset input only resets i.MX6 (all other peripherals are being reset in u-boot independent from WDOG or POR boot).

My expectation from a SOC/MCU is, that even after a "warm" reboot all internal peripherals should work as intended.

How is reboot done on SabreAuto? I think there is also no connection between WDOG and POR.

Best regards

 Martin

[Yuri]

Hello,

  The issue is that the WDOG internal reset is not "hard".
The SabreAuto has WDOG options to reset (boot) parallel NOR flash.

Regards,

Yuri.

[mahi]

Hi Yuri,

  The issue is that the WDOG internal reset is not "hard".

Why is this an issue? Why does the reset have to be "hard"? Is there a proper explanation somewhere?

I know, that when the processor is in some power saving state with reduced voltages and LDO bypass enabled, there will be issues with soft reset. As neither power saving nor LDO bypass is used, that shouldn't be a problem for us.

Best regards

 Martin

[Yuri]

Hello,

  Customers can use Table 60-4 (SRC reset functionality) of i.MX 6Solo/6DualLite Reference Manual,

Rev. 4, 07/2018 regarding difference between reset types.    

Regards,

Yuri.