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DS90UB913A-Q1: DS90UB913A-Q1

user4714671
Prodigy 40 points
Part Number: DS90UB913A-Q1

In our product we got 913 devices on the camera side and 914 devices on the system side. 

Most of the cameras and system work, but we got two 914 boards and one 913 that fails. The specific 913 and 914 boards fails when they are paired but work when they are paired with other 913 and 914 board.

The issue is that the I2C communication randomly stops working. 

Lock is never lost.

The scope traces are:

Yellow: 913 data
Blue: 913 clock
Pink: 914 data
Green: 913 Clock

Resetting the system resolves the issue unit the next failure.

The POC voltage is 12V that is created by a boost circuit on the 914 board.

The POC is provided on both boards with the same circuit.

I replaced R17 with ferrites on both boards, but did not solve the issue.

I added more capacitance to the POC circuits, but it did not solve the issue.

Any sugestions?

  • 0
    TI__Genius 12866 points

    Hi,
    Are you checking lock by inspecting LED or probing.

    Would you be able to check when I2C fails,
    -LOCK is high(by probing LOCK output signal)
    -PCLK frequency is valid

    What value are you using for pullup resistors on SDA/SCL lines.

    Charley Cai

  • 0 in reply to Charley Cai
    Prodigy 40 points

    Hi Charley

    I probed lock with a scope and notices no transitions. Lock remains valid all the time.

    We are using the clocking method on the 913 where the 913 receives a oscillator generated clock on pin 18 (CLKIN) and provides a clock to the sensor on pin 17 (CLKOUT). PCLK is not used for 913 timing in this mode. We are using this clock mode because the sensors PCLK is blanked during vertical sync periods.

    We are using 4.7k ohm pull-ups on the 913 and 914 I2C. The I2C clock frequency on both devices are 100kHz.

    Some more things that we observed:

    BIST does not fail.

    The I2C interface does not fail when the 913 and sensor are provided with power from an external source.

  • 0 in reply to user4714671
    TI__Genius 12866 points
    Moved to Email discussion