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Original question:

DS90UB953-Q1: DS90UB953 CLOCK MODE QUESTION

DS90UB953-Q1: DS90UB953-Q1 clock mode

Jessica Wu74
Expert 6180 points
Part Number: DS90UB953-Q1
Other Parts Discussed in Thread: DS90UB933-Q1

Hi team,

Could you please kindly help to confirm if customer want to use a REF clock to image sensor,(we are not recommend them to do like this, and told them if they do like this, the video may not transmission normally, but customer insist to do so), how they can provide a synchronized clock for DS90UB953-Q1 ? Thank you very much for your kindly support.

Best regards

Jessica

  • 0
    TI__Mastermind 30515 points

    Jessica,

    Sorry I can't understand your issue clearly, but one point from your description is that:

    953 can support "a REF clock to image sensor"! in this scenario, you must select one clocking mode to 953 from below two options:

    1. use one external XO to clock 953, the clock freq. is specified in the pair of 953 and 954's datasheet (can be from 50M to 104MHz).

    2. can use 953's internal clock mode

    Regards,

    Steven

  • 0 in reply to Steven(Shenzhen) Shi
    TI__Expert 6180 points

    Hi Steven,

    Thank you very much for you kindly support.

    I mean customer just want to use a REF clock to image sensor but no another external REF clock/internal clock are used in 953(which clock mode is like the DS90UB933-Q1 PCLK mode as following picture shows). I also don't see this kind of clock mode in 953 datasheet, but i confirmed with other BU before, they told me we can also use this kind of mode but not recommend. So i want to confirm if customer use like following PCLK mode, then how could the image sensor's signal can be synchronized with 953. Since there have no pclk pin for 953.

    Thank you & Best regards

    Jessica

  • 0 in reply to Jessica Wu74
    TI__Mastermind 30515 points

    Jessicala,

    1. pls see above answer for your question. If you want to use external clock to drive sensor directly, you only have two options, either adding one more XO for 953 or you use 953's internal clock mode;

    2. 953 has much higher data rate than 933/913a, they have different clock jitter request in the total serial link! During development stage, 953's clock mode can be freshed, so you can refer to TI's update d/s. But anyway, pls refer to below item3.

    3. For your clocking mode, pls refer to TI's 953 d/s in www.ti.com website, you can refer to page16 on 953 sync. / non-sync. / DVP clocking mode Table description. you can use the option2 mentioned in my above message, the setting is shown in d/s as well.

    7.4.1.3 Non-Synchronous Internal Mode
    In the Non-Synchronous Internal Clocking mode, the serializer uses the internal Always on Clock (AON) as the
    reference clock for the forward channel. The OSCCLK_SEL select must be asserted 0x05[3]=1, to enable
    maximum data rate when using internal clock mode, and the CLK_OUT function is disabled. A separate
    reference is provided to the image sensor or ISP. When in CSI-2 mode, the CSI-2 interface may be synchronous
    to this clock. The CSI-2 rate must be lower than the line rate. For example, with the internal clock of 24.2 MHz
    the FPD-Link III forward channel rate is 3.872 Gbps, the CSI-2 throughput must be ≤ 3.1 Gbps (See Table 6).

    Regards,

    Steven