PGA411-Q1: Resolver Feedback Disabled, but Chip SPI Working - No Faults Given By Chip

Derek Cook

Part Number: PGA411-Q1

Hello,

I just encountered an issue in which the resolver tracking loop was disabled, but the SPI from the chip was reporting to me. I was receiving and sending packets to and from the chip with correct SPI. I was not getting any faults from the chip. The FLT GPIO from the chip was not triggered. Also, pulling the reset line to reset the chip did not help. I had to cycle AC power to resolve this issue.

In what cases would this be possible? What can I do to resolve this? Do you have any idea what may be going on? Thank you for your help!

over 5 years ago

0 Arjun_Prakash over 5 years ago

TI__Expert 7599 points

Hello,

Thanks for using the TI Forum.

This is not an issue we have come across Are you able to read DEV_STAT1 register and confirm that there has been an error ?

Section 7.3.11 Fault Reporting in the datasheet provides guidance on the fault status and the state of the FAULT RES pin. .

0 Derek Cook over 5 years ago in reply to Arjun_Prakash

Intellectual 880 points

Hey Arjun,

No errors were given in DEV_STAT1. However, resolver feedback was stuck to 0. I have two resolvers on my motor so I know the motor was moving whereas this resolver read 0.

After AC power cycle, the resolver feedback is correct again.

0 Arjun_Prakash over 5 years ago in reply to Derek Cook

TI__Expert 7599 points

Thanks for the update.

It appears that the power cycle is addressing the issue. Can you clarify what you mean by indicating AC power cycle. Are you referring to the DC power supply of the chip ?

For debug here are the guidelines and app notes. The documents should help address your concerns and provide guidance to proceed and debug.

PGA411 System level debug

A system level trouble shooting guide can also be found here

Trouble Shooting Guide

Please take a look at the content and let us know if the App notes provides you the guidance to proceed.

0 Derek Cook over 5 years ago in reply to Arjun_Prakash

Intellectual 880 points

Hey Arjun,

That is correct, removing power to the chip fixes the problem. So, you aren't aware of any case that could cause the SPI to function, but the tracking loop to stop working? I am using this chip in production, so it's very concerning that I found this issue. Cycling power is not a good solution.

I'll take a look at the documents you shared and see if I can find anything. Thank you!

0 Arjun_Prakash over 5 years ago in reply to Derek Cook

TI__Expert 7599 points

Thanks. Let su know if you have any questions regards to the document that was sent out.

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PGA411-Q1: Resolver Feedback Disabled, but Chip SPI Working - No Faults Given By Chip