Can S12XHZ enter debug mode if it is programmed to boot and operate in special single chip mode with mode switch set to "no" ?

[khusboo]

An instrument cluster freezes / locks up randomly in a moving vehicle. It got locked up when the truck went over railroad trucks or when a trailer was attached via the fifth wheel. It also happened in truck bay with no shock to it.

Could it be that the due to noises in the battery, the S12XHZ enters debug mode and remains stuck at a point until battery is disconnected and connected again ?

[danielmartynek]

Hi,

It could be anything.

It is possible to flash the MCU with a simple code?

This would tell us this is hardware issue in case the problem remained.

Regards,

Daniel

[khusboo]

Yes it is possible to program the MCU with a simple code. What do you suggest i put in the software and check ?

Thanks

Khusboo

[danielmartynek]

Hi,

Try to simplify the code, disable a few peripherals.

Regards,

Daniel

[khusboo]

HI Daniel,

This is a random failure in the trucks and i am unable to reproduce it at my end nor do i have an access to the trucks which is in a far off geographical location.

So, what you suggest, which is a logical step to solving a problem like this one, will not work for me, unfortunately. 

Would it be possible for you to provide more information on this special single chip mode. What is there on datasheet is not sufficient.

thanks

[danielmartynek]

Hi,

In the special single chip mode BDM is enabled and active immediately out of reset. There is a difference in access to several registers. The MCU can enter the mode only out of reset if MODC = 0, MODB = 0, MODC = 0.

I think the MCU goes through reset due to some failure (clock monitor reset, low voltage, cop, illegal address access). And because you have a debugger connected, the MCU enters the special single chip mode.

Regards,

Daniel