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DS90UB948-Q1: No DOUT0/1 output and I2C issue

Betty Guo
Expert 7300 points
Part Number: DS90UB948-Q1
Other Parts Discussed in Thread: USB2ANY

Hi team,

customer use DS90UB947/948, have below issue:

1. input LVDS signal to DS90UB947, but no DOUT0/1 output.

2. 947/948 I2C communication error. They use 927 software code to configure 947, found I2C can't communicate. before, the 927/948 is work.

mroe information:

PDB pin of 947 is pull up to high

MODSEL0 is 0 ; MODSEL1 is 1V (MAPSEL is 1,COAX is 0); 

3.3V/1.8V/1.1V voltage is normal.

could you help give suggestions, thanks.

  • 0
    TI__Mastermind 25955 points

    Hi Betty,

    Please use the USB2ANY to communicate with the serializer via I2C locally to confirm the device responds at its address locally.

    Then, repeat but connect the USB2ANY to the deserializer board to confirm the device responds at its address locally.

    Connect both EVMS with the HSD cable and power them both up.  Measure the voltage on the lock status pin of the 948 to confirm if there is lock or no lock.

    If there is no lock, please power off the EVMS and perform and test for continuity across the cable.

    Ensure that the 947 DOUT0+ maps to RIN0+ of the 948 and that 947 DOUT0- maps to 948 RIN0-.

    What are the MODE_SEL_0 and MODE_SEL_1 switch settings for both the 947 and 948?  1 V above is not clear because either 3.3 V or 1.8 V may be used.  The table in the datasheet and switches on the EVM can be a little confusing because the silkscreen on the EVM or switch may show 1-8 instead of being zero referenced from 0-7 as shown in the datasheet. Please refer to the switch settings in Table 8 so we can have a clearer picture of the strap settings (or share the ratio).

    as a test, try these settings:

    947:

    MODE_SEL_0: Switch 1 high (GND)

    MODE_SEL_1: Switch 1 high (GND)

    948:

    MODE_SEL_0: Switch 1 high (GND)

    MODE_SEL_1: Switch 1 high (GND)

    If this test is successful, then switch the mapsel on both devices to use SPWG bit mapping.

    Sincerely,

    Bryan Kahler