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DS250DF230: DS250DF230

Prodigy 40 points

Replies: 5

Views: 76

Part Number: DS250DF230

Hi:

I'm using DS250DF230 in the design, and I'm doing the PRBS test. The link under test is like this:

322.265625MHz ->  CABLE -> Retimer (10.3125Gbps) -> oscilloscope

I want to use the retimer to generate PRBS. But after I configured the registers, there're no signal outputs. My configuration sequence is shown below:

Referenced from Programmer's guide(SNLU182D)


// Configuration
0xFC, 0x01 , 0xFF 
0xFF, 0x03 , 0x03
0x0A, 0x0C , 0x0C

0x60, 0x90 , 0xFF 
0x61, 0xB3 , 0xFF 
0x62, 0x90 , 0xFF 
0x63, 0xB3 , 0xFF 
0x64, 0xFF , 0xFF 
0x09, 0x04 , 0x04 
0x18, 0x10 , 0x70

0x1E, 0x00 , 0x10
0x0A, 0x00 , 0x0C
 

//PRBS gen
0x2E, 0x04 , 0x04 
0x30, 0x01 , 0x03
0x1E, 0x10 , 0x10
0x79, 0x00 , 0x20
0x79, 0x20 , 0x20 
0x30, 0x00 , 0x08
0x30, 0x08 , 0x08 
0xA5, 0x80 , 0xE0

Any advice will be appreciated, thanks!

5 Replies

  • Hi,

    Can you confirm whether you are using CAL_CLK_IN = 25MHz on your board?

    Cordially,

    Rodrigo Natal

    HSSC Applications Engineer

  • In reply to Rodrigo Natal:

    Hi, Rodrigo

     I have confirmed that I'm using CAL_CLK_IN = 25MHz(50ppm) on my board.

    Regards,

  • In reply to user6207997:

    Hi,

    What values are you observing for the channel registers below on the retimer channel in question that you are working to configure as PRBS generator?

    • 0x02
    • 0x27
    • 0x28
    • 0x78
    • 0x8F

    Cordially,

    Rodrigo Natal

    HSSC Applications Engineer

     

  • In reply to Rodrigo Natal:

    Hi,

    I observed the below channel register values.

      0x02 -> 0x00

      0x27 -> 0x00

      0x28 -> 0x00

      0x78 -> 0x20

      0x8F -> 0xEA

    Regards,

  • In reply to user6207997:

    Hi,

    The retimer CDR does not appear to be locking to your 322.265625MHz reference signal. Some additional suggestions

    • Can you try the next sub-rate frequency up, 644.53125MHz?
    • What signal amplitude are you using, can you try increasing it?
    • Try manually forcing CTLE = 0x00 on this PRBS generator channel. See below.

    Table. Set CTLE Boost Value

     

    STEP

    SHARED/ CHANNEL REGISTER SET

    OPERATION

    REGISTER ADDRESS [HEX]

    REGISTER VALUE [HEX]

    WRITE MASK [HEX]

    COMMENT

    1

    Channel

    Write

    2D

    08

    08

    Enable CTLE boost override

    2

    Channel

    Write

    03

    00

    FF

    Set CTLE boost to 0x00.

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