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DS125BR800A: Asking for DS125BR800A design review and suggestions

SHH
Mastermind 32186 points
Part Number: DS125BR800A

Hi Team,

Customer would like to design DS125BR800A.


Would you please help review  questions and provide your comments?

 Questions:

1. Is HW mode” with-out De-emphasis” same as SMBUS DEM:0dB?


2. If allow MODE pin control in SMBUS mode, will that mode pin still the function to impact SMBUS setting?


3. how to set Transparent Management of Link Training Protocol for PCIe and SAS?(SMBUS Mode& PIN Mode)


4. If VDO will auto-adjust by VID voltage, what is the meaning to set VDO output?
5. For “The DS125BR800A repeater in SAS3 and GEN3 mode is designed to be transparent” is that equal to “bypass”?
so the TX-FIR (de-emphasis) is passed to the RX to support link training. would you please provide mode detail explanation for this?


Here is previously fine-tune result, many VDO setting are not the same. What is the reason to tune VDO instead of tuning EQ?

Fullscreen HBA4_1226.txt Download 
2022-12-26_11:06:16

            START DUMP (TX) UPPER 0xBA        
 28 00 01 00 00 00 18 01 04 00 00 70 00 00 00 00
 a8 80 00 00 00 00 00 a8 80 00 00 00 00 00 a8 80
 00 00 00 00 00 a8 80 00 4c 00 00 00 00 a8 80 00
 00 00 00 00 a9 80 00 00 00 00 00 a8 80 00 00 00
 00 00 a8 80 00 00 38 00 05 00 00 00 00 00 00 00
 00 65 00 00 00 00 10 44 21 00 54 54 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
            START DUMP (TX) DOWN 0xB8        
 20 00 01 00 00 00 18 01 04 00 00 70 00 00 00 00
 a8 80 00 00 00 00 00 a8 80 00 00 00 00 00 a8 80
 00 00 00 00 00 a8 80 00 4c 00 00 00 00 a8 80 00
 00 00 00 00 a8 80 00 00 00 00 00 a8 80 00 00 00
 00 00 a8 80 00 00 38 00 05 00 00 00 00 00 00 00
 00 65 00 00 00 00 10 44 21 00 54 54 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
            START DUMP (RX) UPPER 0xBE        
 38 00 01 00 00 00 18 01 04 00 00 70 00 00 08 00
 aa 80 00 00 00 08 00 aa 80 00 00 00 08 00 aa 80
 00 00 00 08 00 aa 80 00 4c 00 00 08 00 ad 80 00
 00 00 08 00 aa 80 00 00 00 08 00 ad 80 00 00 00
 08 00 aa 80 00 00 38 00 05 00 00 00 00 00 00 00
 00 65 00 00 00 00 10 44 21 00 54 54 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
            START DUMP (RX) DOWN 0xBC        
 30 00 01 00 00 00 18 01 04 00 00 70 00 00 08 00
 a8 80 00 00 00 08 00 a8 80 00 00 00 08 00 a8 80
 00 00 00 08 00 aa 80 00 4c 00 00 08 00 ac 80 00
 00 00 08 00 ac 80 00 00 00 08 00 aa 80 00 00 00
 00 00 ad 80 00 00 38 00 05 00 00 00 00 00 00 00
 00 65 00 00 00 00 10 44 21 00 54 54 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

6. Is there any concern if not set in AUTO RX-DETECT?

 

 

Thanks for help!

 

Scott

  • 0
    TI__Guru*** 146055 points

    Scott:

        Ticket is assigned and reply maybe delayed due to holiday.

    regards

    brian

  • 0 in reply to Brian Zhou
    TI__Guru* 93670 points

    Greetings,

    1). Without de-emphasis enables linear mode - allowing SAS3 or PCIe link training sequence to pass through the device.

    2). MODE pin takes priority. If MODE pin is set for 20K to GND then de-emphasis is disabled.

    3). Transparent mode is enabled by setting MODE pin through 20K to GND without de-emphasis.

    4). In transparent mode, VOD settings is DC gain - low frequency or long string of ones or zeros gain.

    5). Transparent mode allows link training to pass through the device. Device is operating in linear mode.

    6). PCIe requires auto-detect. On the other hand, SAS3 uses 50-ohm termination(auto-detect disable).

    Regards,Nasser