DS80PCI402: Application doesn't work

Casper Lee

Part Number: DS80PCI402

I have design a Extender Board by using DS80PCI402 for M.2 SSD.

And use the Pin Mode for DS80PCI402. The Problem was it did work properly all the time.

In the beginning , i suspect there were a layout mistake, so i use a spare board then connect TX & RX by a Jumper wire, It can work properly. Means the layout may not a root cause to make this happen.(Jumper Pin1 to Pin 45,Pin2 to Pin 44 and Pin 10 to Pin.35 , Pin11 to Pin36 )

Does anything wrong to cause this kind of issue? Setting or Strapping value?

AMT18033-0710.pdf

over 7 years ago

0 Lee Sledjeski over 7 years ago

TI__Mastermind 43795 points

I do not see anything wrong. Do you have the EQ set to minimum and DEM set to 0 dB?
Regards,
Lee

0 Casper Lee over 7 years ago in reply to Lee Sledjeski

Prodigy 100 points

Yes,I have tried couple setting for EQ , DEM as well. Does possible because there was no AC Cap on the other side?

0 Lee Sledjeski over 7 years ago in reply to Casper Lee

TI__Mastermind 43795 points

Can you be more specific about "does not work all the time"?
These devices do require AC coupling. For PCIe the AC coupling is typically found on the same PCB as the PCIe TX.
Regards,
Lee

0 Casper Lee over 7 years ago in reply to Lee Sledjeski

Prodigy 100 points

The usage scenario is an extender between PC Host and M.2 SSD, so it would not getting longer like other application.Pretty much <5 inch.
When connect PC -> Extender -> M.2, it cannot be properly detect by PC Host. I tried to measure Tx & Rx signals, It's going to High level with little pulse. it seems mean cannot initiated properly on Rx or Tx.
when you said devices do require AC coupling, does it mean both side need to add AC coupling cap instead of one side only?

0 Lee Sledjeski over 7 years ago in reply to Casper Lee

TI__Mastermind 43795 points

Hi Casper,

Yes there needs to be AC coupling between the DS80PCI402 and all PCIe Tx and Rx connections.
The RXDET pin should be Floating (I think it is already, but want to make sure)

Regards,
Lee

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DS80PCI402: Application doesn't work