TUSB7320: some question on TUSB7320

Shu-Cheng LIN

Part Number: TUSB7320

Hi Sirs,

Sorry to bother you.

Please help review of the TUSB7320I as below.

The other issues are as follows:
1. Is SCL/SDA not directly pulled down?
2. Does Power 3.3V and 1V have the order of switches?
3. As shown in the block diagram on the first page, my source is PCI host. How does TUSB7320I's WAKE# / CLKREQ# connect? WAKE#  Pull high / CLKREQ#  Pull down?
4. When do I need to use EEPROM? Isn't the preset correct?
5. Is there any special attention to Layout? Please also provide a Layout guide.

Thank you.

over 6 years ago

0 Brian Zhou over 6 years ago

TI__Guru**** 152820 points

we review the schematic , it may take two or three days

0 Shu-Cheng LIN over 6 years ago in reply to Brian Zhou

Guru 11785 points

Hi Sirs,
Thanks for your reply.
Please let us know if there have any suggest.
Thanks!

0 Brian Zhou over 6 years ago in reply to Brian Zhou

TI__Guru**** 152820 points

1: pulldown will disabled I2C
2:3.3v should be on after 1.1v since 3.3v is used for GRST
3: in our EVM, Wake# and CLKREQ# are directly connected to pcie connector
4: On a PCIe Add-in Card, an EEPROM is only needed if a any of the following is true: • Mark one or more USB ports as nonremovable. • Disable one or more USB ports. • Set a PCIe Subsystem ID and Subsystem Vendor ID. • Change the default de-emphasis/swing/equalizer settings of the SuperSpeed USB ports. • Change the default L0s and L1 latency values for PCIe. • Change the default PWRON polarity to active high instead of active low
5: pls follow usb layout document slla414 from ti.com

0 Shu-Cheng LIN over 6 years ago in reply to Brian Zhou

Guru 11785 points

Hi Sirs,

Thanks for your reply.

So is there any suggestion for our schematic?

In our case, it is a stand-alone PCI to PCIe card. So we don’t support PCIe wake# and there is no I2C interface between motherboard and our card.

I still have a few questions as below:

Can I just pull down the I2C to disable it?
We don’t support PCIE wake#, so can I pull high the WAKE# to 3.3V?
Can I pull down the CLKREQ# to GND directly for PCIe clock always ON?
In our case, we only used USB2.0 on TUSB7320 but no USB3.0. Do we need to implement the EEPROM?

0 Brian Zhou over 6 years ago in reply to Shu-Cheng LIN

TI__Guru**** 152820 points

schematic looks fine.
1: yes, you can pulldown if don't use it
2: be careful, wakeup# pin is not failsafe, you van not have 3.3v on wakeup# when VDD33 is off
3: it's ouput pin. if not use, you can leave it open
4:if you just use our default setting and don't want to change anything, no need to implement EEPROM

0 Shu-Cheng LIN over 6 years ago in reply to Brian Zhou

Guru 11785 points

Hi Sirs,
Thanks for your reply.
Regarding to item2, So I can leave WAKE# pin open if I don’t need wake up function?

0 Brian Zhou over 6 years ago in reply to Shu-Cheng LIN

TI__Guru**** 152820 points

yes

0 Shu-Cheng LIN over 6 years ago in reply to Brian Zhou

Guru 11785 points

Hi Sirs,

Thanks for your reply.

Please refer to the attachment, the schematic has been modified as recommended, please help to review again.

As mentioned earlier, 3.3V must be opened later than 1V, so add power switches to turn on the power of 3.3V from 1V power good. Is this correct?
Or can 1V and 3.3V be opened together? Because there is no need for context from the Power-up sequence in the datasheet?