DS64BR111: SATA Redriver

Hi Jacek,

Do you have a schematic so I can see all the device connections?  The "default" equalization can be quite high which could cause issues as the datarate is increased.

Regards,

Lee

Thanks for fast response. How can I send you the schematic? e-mail address?

Jacek

lee.sledjeski@ti.com

Hi Jacek,

Thanks for the schematic connections.  Since you are using the devices on both ends of the cable there is probably room to reduce the equalization.  I would recommend to start with less CTLE and disable DEM to establish a baseline.  Set DEM pins to 00 for a 700 mV output.

For the equalization (EQ) pins controlling ports connected to the SATA drive and the system controller, I recommend minimum EQ (pin settings 00).

For the equalization (EQ pin controlling ports connected to the SAS cable, I recommend Level 2 EQ (pin settings 0R).

Optimizing for 6G operation may require additional tuning, but this ensures the repeaters do not increase the jitter by over-equalizing the incoming signal.

Also, can you describe what happens in the non-working case. 

No drive seen by system?

Only operates at 3.0 Gbps?

Regards,

Lee

Thanks for those suggestions. I'll try in the near future.
The fail is simply the SSD is not seen by the system. But there is more to it. This verification is done on different than Windows platform. When I put this non functioning link on the windows 7 based system it works fine with relatively high score, showing performance very similar to the SSD I have as a system SSD from my laptop. For that to happened I had to format external SSD to the windows format. But the link performance should not be dependent on the SSD format.

Thanks,
Jacek

Hi Jacek,
You should also try to pull the MODE pin high - current SATA devices are more particular about the OOB timing information during system initialization. Pulling the MODE pin high may improve the OOB response in your case.
Regards,
Lee

Thanks,

I just wanted to make sure I got the EQ right; you said =>For the equalization (EQ) pins controlling ports connected to the SATA drive and the system controller, I recommend minimum EQ (pin settings 00).

Does it mean B0 and A1?  or according to the data sheet EQB0 and EQA1 [those are on SATA side on my schematic]?  and they should got 00.

and then remaining EQA0 and EQB1 should become 0R?

Just wanted to make sure my understanding is correct?

Jacek  

Hi Jacek,

I was recommending to try minimum equalization.

EQA0 = EQA1 = EQB0 = EQB1 = 0

Regards,
Lee

Thanks for hand full of suggestions. I'll try to implement them sequentially and let you know the outcome.

Jacek

SD_TH = 0 , would this need to be done for redriver on the computer side?

I did that on the SSD side and redriver windows based system cannot recognize SSD anymore.

Jacek

SD_TH = 0 on the SSD side caused the disk is not seen even by windows based PC system.

I'll try SD_TH Float

IS DS125BR111 pin compatible with DS64BR111?

Thanks,

Jacek 

Hi Jacek,

Yes it is 100% pin compatible.

Regards,

Lee

We are still looking for the optimum setting selection. Is there an option to ask you to perform the evaluation of of our link? Basically if we would send you the hardware [two SATA repeaters with 7mSAS cable between them to capture the eye-opening diagram which would answer the question of the link margin.

Thanks,

Jacek 

Hi Jacek,

How are you driving and receiving signals with this hardware? It is often difficult to make customer hardware work in our lab which may not be optimal to handle this type of form factor.

Regards,
Lee

Hi Lee,

on the board we have standard SATA and SAS connectors. We would be interested in two boards connected with ~7m SAS cable and then we would have two standard SATA connectors on both ends. Would that feed your hardware?

Hi Jacek,

My bench test equipment uses SMA connectors and cables.
How do you power the hardware?

We have single +5V [110mA] power supply point. Cables would be provided.
Do you have a PCB that converts SMA to SATA?

I modified VOD_SEL to FLOAT selecting 1000mV swing for B channel [A channel is set to 700mV in pin configuration mode] and it looks like curing the problem. This is the channel that drives the long SAS cable. But the question is how much margin do we have, in other words how robust the link is?
I noticed also the equalizer selection I have is from raw 5 [Table 2 of the specification] R0 with is suitable for FR4 20inch trace and would rather need to implement 8m one which is raw raw 10 Float R - although it works well on the laptop @ ~2.5Gb/s speed.
So margin verification would be required.

I do have a basic adaptor for SATA data cables.  Here is a link just to make sure they can fit your board.

https://www.sincsquared.com/sites/default/files/SATA%20to%20SMA%20Prelim%20Data.pdf

Regards,

Lee

It looks like that's the missing piece.
I'll send the picture of the SATA connector from our board to your e-mail.