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DS90UB953-Q1: Net Data rate calculation on Forward Channl

Narasimha venkataravanappa
Prodigy 120 points
Part Number: DS90UB953-Q1

Hi,

we are working on 1.7Mp camera with 953 serializer.

W are using AR0220 1820x940 imager with 953 serializer.  36 frames per second, 12 bits per pixel , MIPI line blanking 4421
could you please  let us know how to calculate net data rate on serializer.
also how to consider line blanking and frame blanking for MIPI 400Mhz.

Please provide the formula for converting Net data rate?

Regards,

Narasimha LV

  • 0
    TI__Expert 3055 points
    Hi Narasimha,

    Here is the general formula that can be used to calculate the CSI-2 throughput:

    Total data rate = [# active horizontal pixels + horizontal blanking] x [# active vertical lines + vertical blanking] x [frame rate] x [# bits/pixel]

    I'm not sure what you mean when you say you are using "MIPI line blanking 4421", but for example, assuming horizontal blanking of 182 and vertical blanking of 5,

    Total data rate = [1820 + 182] x [940 + 5] x [36] x [12]= 817.3 Mbps

    The FPD-Link rate includes some additional overhead and the required FPD-Link line rate can be calculated as:

    Required FPD-Link line rate = 817.3 Mbps x 40/32 = 1.021 Gbps

    The FPD-Link line rate for your system will depend on how you have configured it. If you are using the 953 in synchronous mode, with a 50 Mbps back channel and a 25 MHz reference clock to the 954, the line rate is as followed:

    FPD-Link line rate = BC x 80 = 50 Mbps x 80 = 4 Gbps

    This is more than your required line rate so this setup would be fine.

    In terms of the CSI-2 output of the 954, you can choose the nominal output rate to be anything greater than or equal to the CSI-2 input on the 953. However, the actual throughput rate cannot be faster than the input rate.

    Regards,
    Zoe
  • 0 in reply to Zoe Nuyens
    Prodigy 120 points

    Thanks for the response.


    Can 933 Serializer supports data rate for 36FPS with AR0220 1820x940 imager ,12 bits per pixel .
    Could you please share the FPD-Link line rate?

    Thanks & Regards,
    Narasimha LV

  • 0 in reply to Narasimha venkataravanappa
    TI__Expert 3055 points
    Hi Narasimha,

    Does your imager output CSI-2 data?

    The input to the 933 is a parallel interface whereas the input to the 953 is a CSI-2 interface.

    Regards,
    Zoe
  • 0 in reply to Zoe Nuyens
    Prodigy 120 points

    Hello Zoe,

    Yes, The imager output is CSI2 data, 400MHz MIPI Clock.

    we have an FPGA to convert CSI2 to Parallel interface. could you please share the formula for converting net data rate using 933 serializer for AR0220 (1820*940) with 36FPS.

    Regards,

    Narasimha LV

  • 0 in reply to Narasimha venkataravanappa
    TI__Expert 3055 points
    Hi Narasimha,

    For the 12-bit mode, Line rate = f_PCLK × (2/3) × 28; for example, f_PCLK = 100 MHz (maximum supported PCLK), line rate = (100 MHz) × (2/3) × 28 = 1.87 Gbps maximum line rate.

    In terms of the image data throughput, this will be the fPCLK x 12 in 12-bit mode so a maximum of 1.2 Gbps is supported.

    Regards,
    Zoe
  • 0 in reply to Zoe Nuyens
    Prodigy 120 points

    Hi,

    Could you please explain how you considered 182 is horizontal blanking and 5 is vertical blanking? for AR0220 Imager with 953 Serializer.

    if we use 933 serializer with FPGA what is formula for actual bit rate calculation for 933 FPD link III.

    Regards,

    Narasimha LV

  • 0 in reply to Narasimha venkataravanappa
    TI__Expert 3055 points

    Hi Narasimha,

    Those are simply example numbers for the blanking. The actual blanking will depend on your imager setup.

    I'm not sure what exactly you are asking for here. If you want to know how to calculate the bit rate of the imager, the same calculation applies as before:

    Total data rate = [# active horizontal pixels + horizontal blanking] x [# active vertical lines + vertical blanking] x [frame rate] x [# bits/pixel]

    Regards,

    Zoe