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LP8556SQ-EVM: some address questions of LP8556SQ-EVM

Jimmy Lai
Expert 6845 points
Part Number: LP8556SQ-EVM

Dear Team,

I have some address question as below,

1. I placed the command 0xc4 at the address of 0x71, the brightness of the panel is only 60%, but I did not see this position on the SPEC.

2. i2c_ctrl 0 0 0x2C0  0x71 0xC4--> What is this control for?

Many Thanks,

Jimmy

  • 0
    TI__Genius 9630 points

    hi Jimmy

       We have an additional registers that are normally for internal test,

       0x71  read/write for trim EPROM

        But I do not see any registers with the address 0x2C or 0xC4

  • 0 in reply to Mason Wang
    TI__Expert 6845 points

    Hi Manson,

    We appreciated your great support!

    But I do not see any registers with the address 0x2C or 0xC4.

     

    ==>0x2C : the I2C address of the chip LP8556SQ

    ==>0xC4(1100 0100): write this value into the 0x71 register address.

    In my design,

    I don't have the eeprom chip as above design.

    I want to know why I can turn down the brightness while enter the 0xC4 into 71h.

    Many Thanks,

    Jimmy

  • 0 in reply to Jimmy Lai
    TI__Genius 9630 points

    hi Jimmy

       Per my understanding, this register has the below functions:

    1. update register 90h-9Fh with values from EPROM

    2. or customer can also update the values in 90h-9Fh to EPROM.

    3. the last four bits are read only as the indicator of 32-bit EPROM

    So based on this, I would like to know

    1. what is the version of the device E0X?

    2. when you write 0xC4 to 0x71, you mentioned the brightness changed from 100% to 60%? any other changes?

    3. from you action, 0xC4(1100 0100) means that you did read action and write action at the same time, can you  try to set 1000 0100 or 0100 0100 and see the result?

    Actually, configuration for this register is not normally used, I may need more information from your side for analysis. thanks

  • 0 in reply to Jimmy Lai
    TI__Genius 9630 points

    hi Jimmy

      Any update for this thread? thanks