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Original question:

DS90UB941AS-Q1: DS90UB941 DSI interface/connector parameter

DS90UB941AS-Q1: TDA4VM-EVM__DS90UB941-register-0x00 always 0 after power up

alvin zhang
Prodigy 70 points
Part Number: DS90UB941AS-Q1


Hi, 

We try to enable 941 on the TDA4VM-EVM board. The ENABLE_DSS_DSI is enabled. 

API appDssConfigureUB941AndUB925 in vision_apps/utils/dss/src/app_dss_soc.c is done. 

But there is a confusing problem.

What go wrong? 
Best Regards，
Alvin

  • 0
    TI__Mastermind 34625 points

    Hi Alvin,

    Thank you for including a screenshot of the code. A common cause for the UB941AS to return 0x00 for all registers is an incorrect I2C address. Can you confirm the IDx strap setting and the I2C address you are using for your hardware?

    In the code I see that the I2C address of 0x16 is used. Try using the 8-bit address 0x2C. I am not familiar with the I2C command set you are using but it is common to use the 8-bit address instead of the 7-bit address.

    Best,

    Jack

  • 0 in reply to Jack Scherlag
    Prodigy 70 points

    Hi, 

    We believe the I2C address of 0x16 is right. There are several reasons.

    (1) we have this test on the TI-EVM board, and the official hardware schematics tell us it. There seems no reason to doubt EVM board and psdkra sdk. 

    (2) UB941 datasheet tell us "_UB941" from register 0xF0 to 0xF5. Board_i2c8BitRegRd(0x16, 0xF0..0xF5) return "_UB941". We think the I2C channel is right. 

    Note:  Board_i2c8BitRegRd() is TI-psdkra API. 

    If the I2C address of 0x16 is right, why UB941 has no its 7-bit address of serializer??

    Best Regards，
    Alvin

  • 0 in reply to alvin zhang
    TI__Mastermind 22946 points

    Hi Alvin,

    Please see if the issue is from the below checkpoint.

    1. For 0xF0 - 0xF5, lu8_rix was read as an integer, but it is not clear if the other registers (red box) are integer type.
    2. If so, format specifiers for 0xF0-F5 are used as %x, but it doesn't seem to use %x specifiers for others. (yellow box)

    Best,

    Josh

  • 0 in reply to Josh Baik
    Prodigy 70 points

    Hi,

    I'm sorry, you're right.
    I should be ashamed of making a mistake like that.
    Thanks very much.

    Best Regards，
    Alvin