The question on watchdog reset circuit at i.mx6 dual lite.

[sang-raelee]

Hi, my name is SangRae Lee.

We have used i.mx6 Dual Lite for our products.

Now, we are testing watchdog function and are reviewing watchdog reset circuit drawing by our former engineer.

And we already asked question on watchdog reset circuit via another route but we can not get proper answer from experts except that NXP reference circuit is same with our circuit.

Below is our watchdog reset circuit.

If you can not see image file, then please refer to attached file.

What is the purpose or role of reference number C99(2.2uF) ?

Thank you.

Goodbye.

Best Regards.

SangRae Lee.

[sang-raelee]

Hi igorpadykov.

Thank you for your opinion.

I have wondered why we must add series capacitor to watchdog reset line.

We have used NXP i.mx 6 Dual Lite and NXP MMPF0100F0ANES(PMIC).

Is there any problem between those devices related to watchdog reset interface such as timing characteristics without 2.2uF series capacitor? 

We have had no experience in this case.

In general, we know that the purpose of series capacitor is for DC blocking in digital circuit.

If you know some other using case for series capacitor except DC blocking case, then please help me.

Thank you.

Goodbye.

Best Regards.

SangRae Lee. 

[igorpadykov]

Hi SangRae

seems this is used for providing short reset pulse (avoiding hold PWRON always low).

Best regards
igor
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------