MC33907/33908 Watchdog Disabling

[pederrogo]

Hello,

We are using MPC5774P together with System Basis Chip MC33907/08. At ECU power-up we would like to have the external watchdog in MC33907/08 disabled as long as we are running in the bootloader. Then, when we enter the application SW the watchdog window is set to an appropriate size.

We are using the following sequence in bootloader SW:

1. After power on reset the INIT FS phase is started. This phase is active until first watchdog kick or timeout after 256 ms.

2.  Watchdog registers in SBC are initialized, including watchdog disabling by setting watchdog window size to 0 ms.

3. One watchdog refresh is sent from 5744P -> Exit of INIT FS state.

Is this sequence correct?

Commnets?

Best Regards,

Peder Rogö

[martin_kovar]

Hello Peder,

I had asked my colleague and he told me the sequence is correct. I have only one point. You should do the initialization and first refresh within 256 ms.

Regards,

Martin

[xiaoxisun]

Hi Martin,

   Base on my test, It seems like even if when 33908 running in debug mode, it will still reset(rstb pulled down) if the first refresh are overtime(256ms).

   So I want to ask Is there anyway that we can do a first refresh overtime without reset ?

Thanks,

Xiaoxi

[mayingge]

Hi

Have you solve the issue?I have met the same problem with you,I will  appreciate if you could help me.