MC9S12DG128

[LAR]

Hi,

I use to use the MC9S12DG128BCPV on a board that must operate at -32C, which it did, no problem. 

Now that the leaded BCPV is no longer available, I have switched to the Pb free CPVE version.  My first two boards now both fail at -32C and it appears that the micro is not running. 

I still have more tests to do to confirm this, but are there any known issues with the Pb free CPVE version at extreme cold temperatures?  It's operating spec is -40C.

Thanks for any help.

[Alban]

Hi LAR,

This is a new question that could be a new thread. Being lazy today, I'll leave it here

The B is linked to the Flash Generation.

B parts were improved in term of endurance and retention and the B was dropped.

B = older Flash.

no B = newer Flash

I would not recommend the use of B parts for new Designs.

Cheers,

Alban.

[LAR]

Oops, sorry.

Thanks for info about the B.

Does that mean for new designs (and older existing designs), we would need to amend the code to write to the newer flash?

Appologies, but I am a hardware engineer, not a software engineer.  Is the flash written to during normal operation or is it where the programming code is stored?

Why do you not recommend the B for new designs? 

We have found that the B version is the only version that works.

Thanks,

LAR

[Alban]

Hello LAR,

As far as I know, there is no change for the user.

No code to update at all, nor hardware.

The Flash can be programmed in both cases. For instance, if the software wants to keep some data even during a loss of power, it will store it in Flash. Same for logging data.

I don't recommend the 'B' because the 'without-B' is better. The 'B' does work though.

Are you saying the temperature problem only occurs with Non-B versions ?

Cheers,

Alban.

[Lundin]

As a sidenote, it is not only the flash that has been changed. 'B' versions (mask 0L85D and 1L85D) are filled to the brim with silicon bugs. There are erratas for pretty much every peripheral. You probably don't want to use 'B' if you are using things like SCI, SPI, flash security etc etc.

[LAR]

Hi,

Thanks for the quick reply's.

Yes, only with the non B versions.  The B versions are ok for cold starts.

Cheers,

LAR

[SteveRussell]

A possible problem area is crystal oscillator start-up.  I believe that there is folklore that low temperature startup is a symptom of not having the right component values in the oscillator circuit.

If the crystal start-up was marginal with the old part, some of the parameter variations in the new part may be enough to prevent low temperature start-up.

Have you reviewed the oscillator component values or tried changing them a little in the more drive direction?

Of course, you will have to retest high temp operation if you change them.