L9963E meaning of VTREF_BIST_FAIL flag

[abtjmehmet]

Hi,

The screenshot below is from the L9963E datasheet DS13636, page 125. Is the description for VTREF_BIST_FAIL here a typo?

It matches exactly the description of a the VCOM_COMP_BIST_FAIL bit in the BIST_COMP register, which makes more sense. I note there is also a VTREF_COMP_BIST_FAIL bit in the BIST_COMP register, how does VTREF_BIST_FAIL compare to this flag?

I can't find any other references to VTREF_BIST_FAIL in the rest of the datasheet.

Best, Jack

[Max VIZZINI]

Hi,

It should read:

VTREF_COM_BIST_FAIL   -->  if the BIST on the VTREF UV/OV comparator fails

Best Regards,

AutoDevKit Team

[abtjmehmet]

Hi Max, thanks for your reply.

Just to be totally clear, do you mean VTREF_COM_BIST_FAIL or VTREF_COMP_BIST_FAIL? I only ask because the term "COM" is also used elsewhere and if this refers to a comparator BIST, it would make sense if the name contained the term "COMP".

Best, Jack

[Max VIZZINI]

Yes, VTREF_COMP_BIST_FAIL

[abtjmehmet]

So does this mean that GPIO_BIST_FAIL::VTREF_BIST_FAIL is the same as BIST_COMP::VTREF_COMP_BIST_FAIL? If so, why are these bits duplicated in two different registers?

[Max VIZZINI]

Double safety storage, I guess...

[abtjmehmet]

Please would you be willing to confirm this? No other bits are duplicated in this way from what I can see. We use these bits as part of our application's power on self test so we need confidence that we are reading the correct data.

If they are indeed duplicated, what happens if I read both the flags and they disagree?

[Max VIZZINI]

Hi,

This Community is dedicated to application developments of AutoDevKit, therefore it is not the right place to request datasheet confirmations. We can only share what we did according to our experience...

For formal datasheet questions please refer to the online support on st.com or to our sales and distributor partners.

Thank you for your understanding.

Best Regards,

AutoDevKit team