AM3359 & tps3823

michael musset

Other Parts Discussed in Thread: TPS3823

Hi,

In my project I'm using the TPS3823 has a watchdog. The WDI signal is connected to GPIO2_3 ( T7 ) .

The problem is that when the board boot, the watchdog reset the board before the processor has the time to boot ... I didn't put any pull up or pull down resistor on the line . I have tried also with GPIO 1_15. But got the same result.

I think that GPIO2_3 is used at boot, but GPIO 1_15, I dont think that it's used at boot ... I'm sure that It's in high impedance.

The Yellow signal is the VDD.

The blue signal is the WDI.

The purple signal is the Reset signal ....

We can see that the component tps3823 try to determin if the input is in high impedance, but for some reason it detect that it's not ....

over 9 years ago

0 michael musset over 9 years ago

Expert 1135 points

You can find bellow an another capture ( to show a zoom of the vdd transition) :

yellow = vdd

blue= WDI

purple = MR signal

0 michael musset over 9 years ago in reply to michael musset

Expert 1135 points

Ok, Thx to Biser Gatchev-XID,

It looks like that the processor is connected to PIN that has an internal pull down resistor.

Thanks TI !

0 Ryan Eslinger over 9 years ago in reply to michael musset

TI__Guru 55940 points

Hi Michael,

This thread was recently moved to this forum. I see that you have marked it answered but I do not see any responses to you. As such, I wanted to check that you did in fact have your questions answered. Could you please confirm?

Very Respectfully,
Ryan

0 michael musset over 9 years ago in reply to Ryan Eslinger

Expert 1135 points

hi,

I've posted an another thread and someone from TI answered me.

The WDI signal was connected to a PIN that is in high impedance with a pull down at boot.

I though that the PIN was in high impedance without pull down, now I understand why the watchdog reset at boot :)

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AM3359 & tps3823