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.

DS90UB953-Q1: 954 REF_CLK configed as 24MHz, the frame rate is not correct.

Part Number: DS90UB953-Q1

Dear, sir

We want to confige sensor frame rate=25fps. And the sensor clk always configed as 24MHz by change reg 0x06 and 0x07 of 953.
1. when we use 954_REF_CLK=25MHz, frame rate=25fps;
2. But when we use 954_REF_CLK=24MHz, frame rate=24fps;
3. All other registers not been changed. The only difference is the clock freq of 954. And I am sure that the frame rate of sensor has a relationship With 954.
4. 954 spec shows that 954 ref clk can be 23~26MHz, but the default freq is 25MHz, is there some regs to set freq? I can’t find the setting regs of ref clk, 0xA5 reg is readonly.

  • Hi Lei,

    In a sync mode system, the refclk is used to determine the back channel rate and forward channel (FC) rate by locking all of the sensors and the receiver to a common reference in the same clock domain. Therefore, by adjusting the refclk to 26MHz, you'll have a FC of 4.16G and if you use 25MHz, the FC will be 4G. This also will change the CLKOUT slightly; therefore, you have to adjust the CLKOUT signal if you are using 25MHz vs 26MHz. Since you are using the CLKOUT signal to provide the clock to the imager, I believe it is directly affecting the fps. When you use 26MHz Refclk, try setting registers 0x06 and 0x07 on the 953 to 0x26 and 0x91 respectively and see if the fps stays the same. You can also try setting 0x06 and 0x07 to 0x21 and 0x18 if the first values don't give the results mentioned.

    Regards,

    Mandeep Singh