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DS90UB936-Q1: What is the maximum resolution and fps configuration of the test pattern?

Chris Liu
Prodigy 210 points
Part Number: DS90UB936-Q1

Hi,

When I try the test pattern resolution 2560x2880, 30fps, there are a lot of MIPI error messages form my SOC.

And the resolution 2560x2880, 15fps works well.

The MIPI CSI is configured as 800 Mbps serial rate(register 0x1f = 0x2), 4 data lanes(register 0x33 = 0x1).

So I want to know how to check or calculate the maximum resolution and fps configuration?

Thanks a lot.

  • 0
    TI__Expert 8030 points

    Hi Chris,

    Could you please provide the CSI data type of the data that you are sending? I need this information so that I can calculate the CSI-2 data rate required for the given test pattern resolution. Is the test pattern sending data in the RGB888 format, or is it using a different format?

    Additionally, I have the following questions:

    Does the CSI-2 port of your SOC operate with a continuous clock, or does it use a non-continuous clock? The CSI-2 clock mode that the DS90UB936-Q1 is configured for should match the CSI-2 clock mode of the SOC.

    Is the DS90UB936-Q1 configured such that it uses the same number of CSI-2 lanes as the CSI-2 port of the SOC?

    Regards,

    Kenneth

  • 0 in reply to Kenneth Arnold
    Prodigy 210 points

    Hi Kenneth,

    I'm looking for the yuv422 and yuv420 format for testing.

    My SOC can operate with both continuous and non-continuous clock, I'm using non-continuous clock currently.

    The CSI-2 Lanes is 4 and it's the same as SOC configuration.

    As I mentioned, I have done the resolution 2560x2880, 15fps test and it works well and it's yuv422 format, running with non-continuous clock and 4 CSI-2 Lanes, so I think the configuration is correct.

  • 0 in reply to Chris Liu
    TI__Expert 8030 points

    Hi Chris,

    Thank you for providing the requested information. 

    I wasn't sure if you were using the 8-bit or 10-bit formats of YUV422/YUV420 for the test pattern, so I went ahead and calculated the supported CSI-2 data rate for both. Here are the required CSI-2 data rates for the specifications that you provided:

    CSI-2 Data Rate for YUV420/YUV422 8-bit (4 lanes at 30 fps): 1,106 Mbps/lane

    CSI-2 Data Rate for YUV420/YUV422 10-bit (4 lanes at 30 fps): 1,382 Mbps/lane

    Based on the results above, the 30 fps test pattern was most likely not working because it requires a CSI transmit speed faster than 800 Mbps. To fix this, I recommend that you set the CSI transmit speed of the deserializer to 1.6 Gbps (this can be done by writing "00" to bits 1:0 in register 0x1F). Doing this should resolve the issues that you are seeing with the test pattern at 30 fps.

    Regards,

    Kenneth

  • 0 in reply to Kenneth Arnold
    Prodigy 210 points

    Hi Kenneth,

    Thanks for the quick reply.

    It works well after configuring the data rate to 1.6Gbps.

    Can I have your calculating formula for reference?

    Thanks.

  • +1 in reply to Chris Liu
    TI__Expert 8030 points

    Hi Chris,

    Here is the formula that I used to calculate the CSI-2 data rate per lane:

    CSI-2 Data Rate (Per Lane) = ((Hres x Vres) x (Frame Rate) x (# of bits/pixel) x (1 + (estimated overhead %))) / (# of CSI lanes))

    Here is the calculated result for YUV420/YUV422 10-bit at 30 frames per second for 4 CSI lanes (assuming 25% overhead):

    CSI-2 Data Rate (Per Lane) = ((2560 x 2880) x (30) x (20) x (1 + 0.25) / (4))

    CSI-2 Data Rate (Per Lane) = 1,382 Mbps/lane

    For YUV420/YUV422 8-bit, the only parameter that changes in the equation above is the number of bits per pixel. 

    Regards,

    Kenneth