DS320PR410: Samsung SSD Enumeration Failure

Hi Alec,

Alec Lin said:

Are there any known interoperability notes, errata, or application advisories involving DS320PR410 and Samsung PM1743?

No, we have not heard of past issues with the Samsung PM1743 or other specific SSD models. Redrivers are simple devices that almost no digital functions so it's very rare for people to report compatibility problems, and after further investigation these typically turn out to be questions of EQ tuning.

Alec Lin said:

If none exist, could you recommend next diagnostic steps or reference register settings to resolve this enumeration failure?

I have some questions:

• Can you share us a photo or a block diagram of your hardware setup? It sounds like your project is an adapter card that accepts a M.2 SSD endpoint, and on the other end of the signal path is a MCIO cable. I assume the cable will be going to a CPU on a motherboard but want to see what the whole setup is like.
• It sounds like you are configuring the redriver in pin mode. In pin mode the EQ setting is controlled by two pins, but your table just says "L0/L1/L2". Can you confirm in more details the EQ strap settings you applied to the two EQ pins?
• Can you provide us the project schematic to quickly check the redriver configuration? You can send it to me in private messages.

Best,

Evan Su

Hi Evan,

I've provided the diagram to you. Please check the private messages. Thank you! 

Hi Alec,

OK, I'm reviewing it and will get back to you as soon as possible. Please try to provide the other details I requested, if confidential you can also send them through private messages.

Evan Su said:

Can you share us a photo or a block diagram of your hardware setup? It sounds like your project is an adapter card that accepts a M.2 SSD endpoint, and on the other end of the signal path is a MCIO cable. I assume the cable will be going to a CPU on a motherboard but want to see what the whole setup is like.

Best,

Evan Su

Hi Evan,

I just provided the cable pinout definition through the message. We connect SSD directly through MCIO to an SFF-8639 cable.

Hi Alec,

OK, thanks. 

I have some questions now about the procedure:

• I'm assuming that your enumeration test involves plugging the SSD into the system while the power is off, then turning the system on and checking within the OS or BIOS that there is a PCIe link and the SSD is detected. If your procedure is different from this, let us know.
  • "Consistently fails to be detected" - no success at all? Or does it work in rare occasions?
  • In the case where the Samsung SSDs are not detected, does performing a warm reset (by restarting the system without turning the power off for example) allow the SSDs to be detected?
  • Is there a method in your system (like an extra port) where you can test if the Samsung SSDs can successfully link with the CPU and be detected without passing through the redriver?

Best,

Evan Su

Hello Evan,

• "Consistently fails to be detected" - no success at all? Or does it work in rare occasions?
  -> No success at all
• In the case where the Samsung SSDs are not detected, does performing a warm reset (by restarting the system without turning the power off for example) allow the SSDs to be detected?
  -> Can't detect Samsung SSDs, even after a warm reset.
• Is there a method in your system (like an extra port) where you can test if the Samsung SSDs can successfully link with the CPU and be detected without passing through the redriver?
  ->
  1. We use another brand's M.2 to the MCIO Adapter (the card uses a different brand, Redriver) with the original system, and the system recognizes the Samsung SSD.
  2. We remove the DS320PR410 from our own designed M.2 to MCIO Adapter and connect the line directly, the system can recognize the Samsung SSD.
  It should be possible to determine that the Samsung SSD itself is functioning normally.

Hi Alec,

Evan is out of office. Someone on my team will get back shortly.

Thanks,

David

Hi David,

Got it. Thank you! 

Btw, another brand's M.2 to the MCIO Adapter I mentioned above, was confirmed to use TI SN75LVPE5411/12 linear redriver.

Hi Alec,

Can you confirm (Or try again) with PD = L and RX_DET = L0?  This places the redriver in a mode where it is always on with termination enabled, in this mode the redriver will simply pass all data between the EP and CPU.  If this does not work, can you confirm the Samsung SSD has ac-coupling caps on the Tx pins?

Hi Undrea,

Alec is out of office. I will answer for him.

Can you confirm (Or try again) with PD = L and RX_DET = L0?
->We’ve already tried with PD = L and RX_DET = L0 and it doesn’t work.

If this does not work, can you confirm the Samsung SSD has ac-coupling caps on the Tx pins?

->Yes, the Samsung SSD has AC-coupling caps on the TX pins.

Best,

Ian Cheng

Hi Undrea,

Do you have any ideas on this?

Looking forward to your reply. Thank you!

Alec

Hi Evan,

Can we replace DSDS320PR410 with two SN75LVPE5412 if it can't be solved at the moment?

Best,

Alec

Hi Alec,

Does this Samsung SSD have ac-coupling caps on the Rx pins by chance?

Looks like you provided some info to Evan via email regarding the EQ settings, can you let me know what EQ settings have been tried?  The initial values and levels provided don't match with the datasheet, there is a pretty wide range of EQ settings.  If the SSD is first detected and the handshake can't result in an established link, maybe more of a SI sensitivity issue with the SSD Rx or Tx.  Have the lowest EQ setting on the 410 been tried?  

I don't suspect using the SN75LVPE5412 would change.

Regards,

Undrea

Hi Undrea,

Samsung SSDs do not have AC coupling capacitors on the Rx pin, nor do any of the other SSDs we tested.

We've tried the EQ index from 0 to 7 and also tried PD = L while RX_DET = L0/L4, but neither of these settings can detect a Samsung SSD.
Could I provide the diagram for your reference?

Best, 

Alec