AM62A7-Q1: Does connecting the USB supply rails (refer Pin connectivity requirements) while the USB signals including RCALIB are NC affect system boot or functionality?

zenanding

Part Number: AM62A7-Q1

We didn’t use the USB module but still connect the VDDA_CORE_USB/VDDA_1P8_USB/VDDA_3P3_USB to the power, and the USB related pin keep unconnected in the design. Due to our PCB Gerber has been released to the factory, we can’t change the net connection now, what will happen for the design? Can the system start normally in this situation？We can only disconnect the VDDA_CORE_USB through update the BOM.

over 1 year ago

0 zenanding over 1 year ago

Prodigy 120 points

Any update?

0 Kallikuppa Sreenivasa over 1 year ago in reply to zenanding

TI__Guru**** 192299 points

Hello zenanding

Thank you for the query and thank you for letting me know over email regarding the thread.

I will review and provide the update.

Quick thought is this should be fine provided the USB driver is not initialized any time and the USB calibration procedure does not happen.

As i understand, the Rcalib resistors are used during USB calibration process.

Regards,

Sreenivasa

0 zenanding over 1 year ago in reply to Kallikuppa Sreenivasa

Prodigy 120 points

If we don't use USB0/USB1 , Then does POWER VDDA_CORE_USB/VDDA_1P8_USB/VDDA_3P3_USB still must be connect to GND? Expext your reply ASAP

0 Kallikuppa Sreenivasa over 1 year ago in reply to zenanding

TI__Guru**** 192299 points

Hello zenanding

Thank you.

I am trying to understand if your question is is it a must to connect the POWER VDDA_CORE_USB/VDDA_1P8_USB/VDDA_3P3_USB to ground as per the pin connectivity requirements.

Is my understanding correct?

regards,

Sreenivasa

0 zenanding over 1 year ago in reply to Kallikuppa Sreenivasa

Prodigy 120 points

YES,you are right

0 Kallikuppa Sreenivasa over 1 year ago in reply to Kallikuppa Sreenivasa

TI__Guru**** 192299 points

Hello zenanding

Thank you.

Kallikuppa Sreenivasa said:
I am trying to understand if your question is is it a must to connect the POWER VDDA_CORE_USB/VDDA_1P8_USB/VDDA_3P3_USB to ground as per the pin connectivity requirements.

This is application dependent and this saves power,

I assume you do not have the low power as a critical requirement.

Regards,

Sreenivasa

0 zenanding over 1 year ago in reply to Kallikuppa Sreenivasa

Prodigy 120 points

OK, thanks very much.

+1 Kallikuppa Sreenivasa over 1 year ago in reply to zenanding

TI__Guru**** 192299 points

Hello zenanding

Please refer below:

Is it Ok if the RCALIB resistor is not mounted for USB0 and USB1 when POWER VDDA_CORE_USB/VDDA_1P8_USB/VDDA_3P3_USB are connected and USB0 and USB1 is not used.

From the USB PHY point of view, it is recommended to initiate the calibration sequence only when the calibration resistor is connected. Initiating the calibration sequence without a calibration resistor is not a valid use case and it may cause unknow results. Therefore, we tell customers they must place the resistor anytime the PHY is powered because we cannot prevent someone from loading a version of the software that initiates the calibration sequence.

The answer is we do not recommend or know the behavior without Rcalib when power is applied to the USB supplies, but it should be okay as long as the software can ensure the calibration sequence is never initiated without the resistors.

Regards,

Sreenivasa

0 Kallikuppa Sreenivasa over 1 year ago in reply to Kallikuppa Sreenivasa

TI__Guru**** 192299 points

Hello zenanding

Pls Edit the title as below:

AM62A7-Q1: Does the USB module power connected while the USB signals floated infect system boot?
Edited to
AM62A7-Q1: Does connecting the USB supply rails (refer Pin connectivity requirements) while the USB signals including RCALIB are NC affect system boot or functionality?

Regards,

Sreenivasa

0 zenanding over 1 year ago in reply to Kallikuppa Sreenivasa

Prodigy 120 points

OK,I see, thank you

0 zenanding over 1 year ago in reply to Kallikuppa Sreenivasa

Prodigy 120 points

I will edit the title as you said, however I don't know how to change it?

0 Kallikuppa Sreenivasa over 1 year ago in reply to zenanding

TI__Guru**** 192299 points

Hello zenanding

Thank you for the note.

No worries, i will take care.

Regards,

Sreenivasa

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AM62A7-Q1: Does connecting the USB supply rails (refer Pin connectivity requirements) while the USB signals including RCALIB are NC affect system boot or functionality?