TPS536C7: FIRST TO ALERT random occur

Hi Eric,

The use of first to assert Bit is when many devices are asserting SMBALERT#. This bit provides a way for the host to know which device was the first to have a problem.

Are there any other devices in your system? If yes, do you see this bit being asserted in any other devices as well? Also do you see the SMB_ALERT# (pin 15) going LOW?

The STATUS_BYTE (78h) /STATUS_WORD (79h) can tell you exactly which fault is asserting the First to Assert bit.

SMBALERT_MASK Bit can be set to avoid setting "First to Assert". But this will also mask the SMB_ALERT# (pin 15) signal.

Thanks & Regards,

Aishwarya

Hi Aishwarya,

In currently design use two multiphase controller shared the same PMBUS and no connect other devices in this bus.

Here is step:

1. I check host register find SMB_ALERT going LOW

2. Check output voltage was ok

3. Connect GUI and see the FIRS TO ALERT is assert

4. Click clear faults then check host register SMB_ALERT going HIGH

5. Try to shutdown and power on many times can see FIRS TO ALERT is assert from GUI

6. Check setting this bit default is 0b

I still not sure what cause FIRS TO ALERT assert.

BR

Eric

Hi Eric,

SMB_ALERT# & hence "First to ALERT" can go low due to multiple reasons other than the output voltage:

Can you please send me the value of follwoing registers (79h) & (78h)?

Hi Aishwarya,

I try a couple times finally see the First to ALERT.

(79h) & (78h) was 0x03 both.

BR

Eric

Hi Aishwarya,

7Eh was 0x01, from the register table has show [Other communication error occurred].

So it's seems like I can't find out the cause of error?

BR

Eric

Hi Eric,

Other communication error can include multiple possibilities. You can check for some of the conditions mentioned in the datasheet under CML_Other.

Thanks & Regards,

Aishwarya

Hi Aishwarya,

Is there any possibility this situation：

Due to we use TPS536C7 "B1" version, but we don't have B1 config only B0 config.

So we use B0 config import to B1 silicon, maybe some setting need to set?

Earlier we use A0 config import to A0 silicon is ok have not see this error occur and I can make sure no change HW design between A0 and B1.

BR

Eric

Hi Fang,

I need to check the difference b/w these versions with the backend team. I will get back to you on this in sometime.

Regards,

Aishwarya

Hi Fang,

The changes b/w the different versions cannot be compared because it involved different kinds H/W & F/W changes. You can email me the config files that the customer uses & I can compare it with the B1 config files that I have to see the difference.

Regards,

Aishwarya

Hi Aishwarya,

Please provide me email address, thanks.

BR

Eric

A-BHATNAGAR@TI.COM

Hi Aishwarya,

Please check the email box for config file, thanks.

BR

Eric

Acknowledged

I will test & let you know by EOD