How to deassert WDOG-output-signal of iMX25

[makotofujimoto]

I'm Makoto Fujimoto.

According to iMX25 Reference Manual,WDOG-output-signal is deasserted after POR-input-signal is asserted.

(Refer to Figure 48-10 "WDOG Time-Out Condition/WDT Bit Is Set")

I want to deassert WDOG-output-signal after the watchdog-timeout occurs.

To do so,iMX25 needs POR-input-signal.

But I want to keep all Powers for iMX25 ON.(Don't want to power off all Powers)

Can I assert POR-input-signal as all Powers ON. (without doing Power-OFF and Power-ON)

And Can I connect WDOG-output-signal to POR-input-signal to deassert WDOG.

Best Regards

[Yuri]

  Hello,

Please refer to the following :

How to deassert WDOG-output-signal of iMX25

Regards,

Yuri.

[makotofujimoto]

Dear all

We want to use POR signal to reset i.MX25 during system working.

Is the POR signal able to be asserted while all power supplies to i.MX25 are stable?

Does i.MX25 need Power up sequence when POR signal is asserted?

If it is so, I don't know the reason.

Best Regards

[Yuri]

Hello,

yes, it is possible to asert POR without power up sequence.

Regards,

Yuri.

[makotofujimoto]

Hello,

I understand your answer.

We want to reset i.MX25 and external Flash memory when watchdog-timeout occurs.

At first I connected WDOG signal to Flash memory's reset pin.

But it is necessary for this method to use POR signal to deassert WDOG signal when watchdog-timeout occurs.

So I am seeking another method now.

Can I use VSTBY_ACK-output- signal to reset external Flash memory when watchdog-timeout occurs.

When watchdog-timeout occurs,internal system reset is performed.Then VSTBY_ACK-output- signal goes L-level,I think.

(In this case ,I don't use WDOG signal)

Best Regards,

[Yuri]

Hello,

please look at my comments below.

> But it is necessary for this method to use POR signal to deassert

> WDOG signal when watchdog-timeout occurs.

The watchdog event provides WDOG assertion and reset to i.MX25,

so the WDOG should be deasserted. "After a time-out, the WDOG Timer
module asserts the internal system reset signal, wdog_rst, which goes to the System

Reset Controller. There is also a provision for WDOG signal assertion by time-out
counter expiration."

  As for VSTBY_ACK - this is output, which  toggles at finish of internal system reset.

This signal may be used, if internal reset is what it is required.

Regards,

Yuri.

[makotofujimoto]

Hello,

I understand below.

I'll finish my question.

Thanks for your reply.

Regards,

Makoto