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Original question:

AM5718: Spread Spectrum Clocking support

AM5706: When using Spread Spectrum Clocking

O.H
Mastermind 6340 points
Part Number: AM5706
Other Parts Discussed in Thread: AM5718

Hi experts,

My customer is designing a prototype board using the AM5706.

Q1:Is it possible for the AM5706 to use the SSC (Spread Spectrum Clocking) function for high-speed signal systems such as DDR and USB3.0?
In the following thread, AM5718 is able to do it, so I think it is possible, but please let me check just in case.
e2e.ti.com/.../2820329

Q2:Am I correct in saying that SSC can be used, but you will not get support from TI?
The following thread looked like SSC itself is not supported, not just SSC as DSS.
e2e.ti.com/.../am5708-video-dpll-ssc-support

Q3:The AM5706 TRM (spruhz7j.pdf) says "only available under proper licensing agreement", but if I want to use SSC, do I need a licensing agreement?

Sorry, but I don't have any knowledge about SSC, so I would appreciate it if you could tell me.

Best regards,
O.H

  • 0
    TI__Guru 54422 points

    Hello OH,

    Spread spectrum is supported only on DSS as documented in this appnote:

    https://www.ti.com/lit/an/spraby0a/spraby0a.pdf

    Regards,

    Kyle

  • 0 in reply to kcastille
    Mastermind 6340 points

    Hello Kyle,

    Thanks for the reply.

    kcastille said:

    Spread spectrum is supported only on DSS as documented in this appnote:

    https://www.ti.com/lit/an/spraby0a/spraby0a.pdf

    I have checked the attached document (SPRABY0A) and I am confused because there is a difference from the description in TRM (SPRUHZ7J).

    • The explanation of "Jacinto6 Spread Spectrum Clocking Configuration (Rev. A)".SPRABY0A

    2.2.3.1 Supported Configurations  As stated before, only use of DPLL_VIDEO1 for spread spectrum clocking is supported.  Table 2 lists the supported configurations.

    2.2.1 Registers Used in Configuring SSC
    NOTE: Only use of DPLL_VIDEO1 is approved for use with Spread Spectrum Clocking. Use of other DPLLs is neither approved nor recommended. Table 1 highlights the registers involved in configuration of SSC in DPLL_VIDEO1.

    →SSC is supported only by DSS(DPLL_VIDEO1).

    • The explanation of "AM571x and AM570x Sitara Processor Technical Reference Manual (Rev. J)".SPRUHZ7J

    →SSC is not supported by DSS(DPLL_VIDEO1).

    The conclusion is that SSC is supported only by DSS in AM57xx, but not by DSS in AM570x (and AM571x). Is this idea correct?

    Best regards,
    O.H

  • 0 in reply to O.H
    TI__Guru 54422 points

    OH, 

    The appnote overrules the TRM in this case, and covers all of AM570x and AM571x AM572 AM574 etc.  

    Regards,

    Kyle

  • 0 in reply to kcastille
    Mastermind 6340 points

    Hello Kyle,

    Thanks for the reply.

    I understood that it can be used only with DSS and no license etc. is required. If I am wrong in my understanding, please point out the additional information.

    Best regards,
    O.H