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DS90UB949-Q1EVM: I2C pass through in DS90UB949 - DS90UB948 FPD-LINK communication

Carlo Pane
Prodigy 10 points
Part Number: DS90UB949-Q1EVM

We have the evaluation board DS90UB949EVM  (SER) connected to our board equipped with DS90UB948 (DESER).

We would like to have HDMI and I2C signals passing froma board to another. Specifically, we would like to have a device connected to the SER communicating

via I2C to a device connected to the DESER, simulating a direct connection between them.

Here you can see a schematic representation of the system:

We've found the document below, but it refers to a different component of the FPDLINK family that has different resgisters:

https://e2e.ti.com/support/interface-group/interface/f/interface-forum/789152/ds90ub949-q1-i2c-pass-through-configuration

https://www.ti.com/lit/an/snla222/snla222.pdf

Without any register modification, we already has the HDMI working, but I2C is not passing.

Can you tell us which register modification we would need, to achive the decribed communication?

  • +1
    TI__Mastermind 31650 points

    Hi Carlo,

    Thank you for reaching out to us. I would happy to assist you from here. If you want to communicate the touch panel and backlight via I2C over the FPD-Link, you need to set the I2C slave ID and alias. Let say I set the touch panel and backlight physical addresses to random number 0x24 and 0x25 respectively. Now, here is what you need to do.

    1. Make sure that you have the I2C pass-through enable 0x03[3] = 1.
    2. Setting the addresses to the slave ID and alias registers. On 949 side, you need to set 0x07 = 0x24, and the 0x08 can be the same address or anything 0x08 = 0x34.
    3. If you have additional address you would like to set, you may use 0x70 and 0x78 for the backlight.
    4. Afterward, you may need to set on the deserializer side, 0x08 = 0x24 and 0x10 = 0x34.

    Hope this helps. Let me know if you have any questions.

    Aaron

  • 0 in reply to Aaron Heng
    Prodigy 10 points

    Thank you very much Aaron! It works!