MC33814 watchdog configuration issue

[basavanagouda]

Hi,

We are using MC33814 IC in our project.

IC watcgdog is configured to 60msec time. we confirmed reset values are configured back to WD config register. But reset board every 10seconds. It is the default value of the register. 

How we can make sure watchdog is configured with user input value? How to configure wd register? 

Is there any pre conditions need to be take care?

Please help us. this issue become a show stopper. 

Thanks,

Basava

[JozefKozon]

Hi Basavanagouda,

please see an answer from an application engineer I have contacted.

DESCRIPTION

The watchdog timer can be configured by writing "1 0 0 1 0 1 1 0" in Reg#10 (Watchdog SPI configuration register). When watchdog is refreshed (bit 7 at "1" in Watchdog SPI control register, Reg#12), all other bits of the register need to remain "0".

There is no way to check that the watchdog timer value has been taken into account, except by reading the time left by rewriting "1 0 0 1 0 1 1 0" in Reg#10 (Watchdog SPI configuration register) right after watchdog refresh.

With Best Regards,

Jozef

[basavanagouda]

Thank for the reply,

I'm configuring the watchdog for 60msec time and refreshing it every 20msec using control register. Watchdog should reset the controller if it's not refreshed. But  the ECIC is reset controller after 10sec. it's taking default value to reset. 

I'm verifying configured register by reading it back. 

How the configured value is changed to default value? If I didn't refresh the watch dog using control register, is it taking default value?

Thanks,

Basava 

[JozefKozon]

Hi Basavangouda,

the application engineer has sent me an answer. Please see the description.

DESCRIPTION

When refreshing watchdog with the control register, bit 7 should be "1" and all bits from 6 to 0 should be "0" so that watchdog timer is reloaded with value of configuration registers. The default value (10 seconds) is reloaded after a RESETB when watchdog is enabled.

Are they able to follow the decounting of the watchdog by reading watchdog status register?

In fact, it would be interesting to have the full sequence of SPI communications you make for watchdog operation as it should work the way you describe it.

With Best Regards,

Jozef