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sn75dp130 in a sink about link training

Rayn
Prodigy 60 points

My question to Ti about link trainin

Our case , use DP130 as sink mode.

1. Doc SLLA349    page 3 AUX iplementation  -  DP130 link training   is disabled,   but page 8,  DisplayPort Sink Link Training Suggestions .  

The DisplayPort 1.2a standard defines a DPCD register, called TRAINING_AUX_RD_INTERVAL, within
the sink that will adjust the timing of the aux read of DPCD link status registers (DPCD address 00202h
thru 00204h) and adjust request registers (DPCD address 00206h and 00207h). Typically, a sink will
default this register to 00h. Changing the default to 01h or 02h will allow more time for the I2C writes to the
DP130’s DCPD registers to complete.

but 0000Eh is read only.  it change the register via  Host I2C  or  AUX ?

2. 8.2 Link Training Clock Recovery (CR) Phase    means :we should change my sink device'DPCD  RD  interval ? how can i control the DP130  

in link training CR phase?

App Note link http://www.ti.com.cn/cn/lit/an/slla349/slla349.pdf 

  • 0
    TI__Mastermind 23815 points
    Hi,

    There is some confusion here, Section 8 provides suggestions for Sink manufacturers. This section is not related to DP130.
    If you are not designing a Displayport sink device you don't have to worry about it.
    DP130 just passes AUX signal from DP source to DP sink, and monitors writing to some DPCD registers.

    Regards
  • 0 in reply to Moises Garcia
    Prodigy 60 points

    Hi Moises

    Thank you!

    We're designing  the sink device,  section 8   means-  sink device need change  DPCD register to adopt the link training flow?

    We follow the SLLA349:pdf to design Hardware and software ,it maybe any issue to concern ?

    Regards

  • 0 in reply to Rayn
    TI__Mastermind 23815 points

    Hi Rayn,

    Got it, The suggestions on Section 8 are just to have a more relaxed deign, if your receiver can handle 100us read interval, then you don't have to worry about it.

    Follow the DP specification, SLLA349 just have some recommendations, it doesn't affect DP130 behavior.

    Regards

  • 0 in reply to Moises Garcia
    Prodigy 60 points
    Hi Moises

    I have another question . when the DP130 detect the DP source input , if DP130 have any register to read for the status?

    BR

    Ryan
  • 0 in reply to Rayn
    TI__Mastermind 23815 points

    Hi Rayn,

    DP130 doesn't detect DP source, what it does is monitor AUX channel for link training.

    When DP source detect DP sink, it starts link training through AUX channel, in default mode DP130 monitors it and configures itself, then, enable outputs.

    For sink applications is recommended configure it via I2C, so, after this configuration DP130 will enable its outputs.

    If you want to be sure the DP130 has be configured, to have to read DP130 DPCD registers.

    Regards