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TLK10031: about HS_EQHLD, HS_EQPRE

YoungYun Kim
Intellectual 410 points
Part Number: TLK10031

To whom may be concerned.

Could you give me an advice for RX Equalizer on TLK10031?


My customer had packet loss on HS Side  and found possilbe solution to solve problem by using equalizer setting, specailly for HS_EQHLD, HS_EQPRE[2:0].


But, Customer has one question for them due to  below phenomenon.
1) when deteced link up, Customer changes the value of  HS_EQHLD, HS_EQPRE[2:0] to 0'b1 and other value rather than default value respectivly.
and checked there was no packet loss.


2) after then made link down and up, keeping register values on 1) step.--> Even thought using same values, Packet loss happened.

3) So, Customer made another procedure for testing.
 a. When detected link up, applied Values which were used at 1)
 b. When detected link up, applied default values on HS_EQHLD, HS_EQPRE
 C. When detected link up again, applied values which were used at 1) again.
 after using this procedures, packet loss didn't happen.
 
 Question)
 Could you let me know why packet loss happend at 2) and why packet loss didn't happend even though using the same vlaue on HS_EQHLD, HS_EQPRE.
 Should we return HS_EQHLD's value to default(0'b0) whenever link become down?

thank you

Best Regards

Mark Kim

  • 0
    TI__Mastermind 19165 points

    Hi Mark,

    If customer simply adjusts HS_EQPRE and leaves HS_EQHLD at default setting, do the packet losses disappear?

    Cordially,

    Rodrigo Natal

    HSSC Applications Engineer

  • 0 in reply to Rodrigo Natal
    Intellectual 410 points

    Dear Rodrigo Natal

    I am sorry for late reply.

    Could you please review test result for packet loss issue on HS side? and let me have your advice.

    I guess if you come up with new idea for packet loss on low temperture, It might be one of best things.

    Please look over below description and Can you confirm if there are any mistakes on default setting as well.

    1. Issue : Packet loss on HS interface.

      Check packet Loss on HS_ERROR_COUNTER register

    2. Default Setting of TLK10031

    　

    Device address

    Register

    address

    Setting
    Value

    Default
    Value

    GLOBAL_CONTROL_1

    0x1e

    0x0000

    0x8610

    0x0610

    HS_CH_CONTROL_1

    0x1e

    0x001d

    0x2000

    0x0000

    CHANNEL_CONTROL_1

    0x1e

    0x0001

    0xb24

    0x0b00

    HS_SERDES_CONTROL_1

    0x1e

    0x0002

    0x831c

    0x831d

    LS_SERDES_CONTROL_1

    0x1e

    0x0006

    0xf115

    0xf115

    AN_CONTROL

    0x7

    0x0000

    0x2000

    0x3000

    LT_TRAIN_CONTROL

    0x1

    0x0096

    0x0000

    0x0002

    TI_RESERVED_CONTROL

    0x1e

    0x8020

    0x03ff

    0x0200

    HS_SERDES_CONTROL_3

    0x1e

    0x0004

    0x6500

    0x1500

    RESET_CONTROL

    0x1e

    0x000e

    0x0008

    　

     

     3. # of Test Samples : 3

    4. Through repeated tests , Customer confirmed below two configuration made less packet loss than other configuration.

    4.1 Default Setting + HS_EQPRE[2:0] : “110” + HS_EQHLD : ‘1’

    4.2 Default Setting + HS_CDRFMULT[1:0] : “00” + HS_CDRTHR[1:0] : “11"

     

    5. Test Result for 4.1 & 4.2

    5.1 Test Result : “ Default Setting + HS_EQPRE[2:0] : “110” + HS_EQHLD : ‘1’ “

    a. There was packet loss on all test samples at low and high , room temperature condition

    b. additional test on setting with setting at “5.1”

    -. HS_ENTRACK (RXG) : ‘1’ – Loss ( No recognizable difference)

    -. HS_H1CDRMODE (RXG) : ‘1’ – link down

    -. HS_EQHLD : ‘0’ – loss ( More loss occurred)

    -. HS_AGCCTL(RXG) : “11” – Loss ( No recognizable difference)

     

    5.2 Test Result : Default Setting + HS_CDRFMULT[1:0] : “00” + HS_CDRTHR[1:0] : “11”

    a. There was packet loss on only low temperature condition

    b. did packet transmission test at Low temperature ( -40 degree)

    c. additional test on setting with setting at “5.2”

    -. Adjust HS_EQPRE[2:0]

    -. HS_EQPRE[2:0] (000 ~110) : Packet loss

    The higher value, the higher loss rate. At value 110, Link was down

     -. Adjust HS_LOOP_BANDWIDTH[1:0] : Packet loss

     Carried out test with 00 ~11

    -. HS_LOOP_BANDWIDTH[1:0] : “01” + adjust HS_EQPRE[2:0] : Packet loss

     

    thank you

    Best Regards

    Mark Kim

  • 0 in reply to YoungYun Kim
    TI__Mastermind 19165 points

    Hi,

    I unfortunately do not have any additional TLK setting recommendations I can provide. The high-speed bandwidth and/or transmitter output settings for the device connected to the TLK chip should be further optimized if possible to reduce jitter at low temperature.

    Cordially,

    Rodrigo Natal

    HSSC Applications Engineer