• State Resolved
  • Locked Locked
  • Replies 9 replies
  • Subscribers 104 subscribers
  • Views 1803 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Linux/66AK2G02: How to establish audio phase synchronization using CS2000 on K2GEVM

Satoshi TOMINAGA
Intellectual 850 points
Part Number: 66AK2G02

Tool/software: Linux

Hi,

I'm trying audio clock synchronization using 66AK2G0x SoC.

Checking the schematics of K2GEVM, the CLK_OUT of CS2000 can be frequency synchronized with PTP clock with CLK_IN of CS2000 connectied to CPTS_TS_COMP signal of 66AK2G02.

To establish phase synchronization, FSX output of 66AK2G02 must be compared with PTP(CPTS) clock to feedback for example,

- restart frame sync generator

- control CPTS_TS_COMP_LOW_VAL/CPTS_TS_COMP_HIGH_VAL

Are there any recommended method to make phase synchronization especially detecting FSX edge in CPTS ?

Regards,

Tommy

  • 0
    TI__Guru 65405 points
    Hi Tommy,

    I've forwarded this to the design experts. Their feedback should be posted here.

    BR
    Tsvetolin Shulev
  • 0
    TI__Mastermind 42545 points
    Hi Tommy,
    I'm checking with the CPTS experts to see if this is possible and how it can be achieved. I'll get back to you once I get a response.
    Regards,
    Bill
  • 0 in reply to Bill Taboada
    Intellectual 850 points

    Hi Bill,

    Thank you for your support.

    I'll wait for the response.

    Regards,

    Tommy

  • 0 in reply to Satoshi TOMINAGA
    TI__Mastermind 42545 points

    Hi Tommy,

    Can you also provided some additional details on what you are trying to achieve with the CPTS? All applications that I've seen with this interface on previous parts were using the CPTS for synchronizing with an Ethernet interface. Your application appears to be different. I want to have as much information as possible when discussing your requirement.

    Thanks,

    Bill

  • 0 in reply to Bill Taboada
    Intellectual 850 points

    Hi Bill,

    Thank your for your support.

    I know that CS2000 is useful to make audio clock synchronized with low frequency (50Hz - ) external clock.
    So, the K2GEVM system can make PTP frequency synchronized audio clock, the source of CLK_IN of CS2000 is generated by CPTS.

    But considering the phase synchronization, for example, Fs = 48kHz, the audio frame duration is about 20 usec. (= 1 sec / 48 kHz) The maximum phase difference is about +- 10 usec.
    So, when considering usec order phase synchronization between devices, the phase synchronization of audio frame clock (FSX) is needed.

    Considering PTP - Audio clock phase synchronization, the PTP second (just N x 10^9 nano seconds) edge matches the audio frame start time.
    Therefore, to establish audio phase synchronization, the edge of FSX must detected by SoC, to match with the second edge of PTP time.
    The feedback from FSX of McASP is mandatory.

    If the K2GEVM system has the performance to establish the audio phase synchronization using PTP, I want to know the detail.

    Regards,
    Tommy

  • 0 in reply to Satoshi TOMINAGA
    Guru 19890 points

    Hello Bill,

    Tommy-san is my customer. Could you please give him some insight on this ?
    PTP synchronized clock is fed to AHCLKX (McASP master clock input for Tx) and would be divided internally for generating ACLKX and AFSX output. After K2G gets synced with a PTP event, McASP register has to be controlled by CPU to release ACLKX and AFSX output and it would take some latency. Eventually, AFSX active edge could be delayed from a PTP event.
    His goal is synchronizing/aligning the active edge of audio clock (McASP Tx Frame Sync, i.e., AFSX) with a PTP event, and he is now wandering if TI might have some solution or idea with CPTS module, something peripherals, and some other external components (In case of K2G EVM, CS2000), for example, something feedback mechanism of ACLKX output timing to CPTS module.
    Do you have any comment on this ?

    Tommy-san, if I missed something, please update us in this thread.

    Best Regards,
    Naoki

  • 0 in reply to Naoki Kawada
    TI__Mastermind 42545 points
    Naoki-san and Tommy-san,
    I did some research and found that the CS2000 component with the connection to the CPTS module was included on the EVM to provide support for future development of Ethernet AVB. No additional software has been generated to add that support at this time. The CS2000 is used in its default mode which is not effected by the CLK_IN connection to the CPTS.
    I don't have any suggestions on how the CPTS could be used to align a PTP event with the McASP signals. The CS2000 can be used to synchronize and external event with the AHCLKR which can be used as a source for the McASP transmit and receive clocks. There is no method for synchronizing an external event with the McASP frame sync unless you have an external circuit to generate the frame sync and use that as an input to both the McASP and any devices connected to the McASP. If the frame sync is generated internally to the K2G, it will not be synchronized to any event.
    Regards,
    Bill
  • 0 in reply to Bill Taboada
    Guru 19890 points

    Hello, Bill-san, Tommy-san,

    Thanks for your reply, Bill-san. Tommy-san, Is this answer your questions ?

    Best Regards,
    Naoki

  • 0 in reply to Naoki Kawada
    Intellectual 850 points
    Hi Bill-san and Naoki-san,

    Thank you for your support.
    I understand the current status of CS2000 on K2GEVM.

    Regards,
    Tommy