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DS90UB947-Q1: Signal transmission problem

Amy Luo
Expert 6895 points
Part Number: DS90UB947-Q1
Other Parts Discussed in Thread: ALP

Hi team,

Sorry bother to you, but our customer has the following problem.

The hardware architecture is in the following link: system B

https://e2e.ti.com/support/interface/f/138/t/896306?tisearch=e2e-sitesearch&keymatch=DS90UB948-Q1%2520master

Questions:

1. When 948 is a primary, how to send data to MCU after 948 receives data from SOC

2. How to configure 948 through MCU, hope to provide configuration reference code

3. Which registers should 948 be configured to run

Thanks in advance.

  • 0
    TI__Mastermind 19720 points

    Hi Amy,

    What MCU are you using? does it have the ability to switch its I2C from master to slave mode?

    1.You can use the 948's mailbox registers to send information from the SOC to the MCU

    2 and 3.The configuration depends on what you are trying to do with the 948. For just FPD-Link in and OLDI out there is little to no configuration.

    Regards,

    Michael W.

  • 0 in reply to Michael.Walker
    TI__Expert 6895 points

    Hi Michael,

    Thank you for your reply. The customer feedback there are the following questions, could you please help to answer

    The MCU can be switched from master mode to slave mode. After switching to slave mode, there are several doubts:

    1.  In slave mode, how to set 948

    2. At present, the functions of 948 are as follows:

    (1) Receive the video signal transmitted from 941 and transmit the video signal to the display screen through LVDS

    (2)Receive the control signal transmitted from 941 and transfer it to MCU through IIC

    (3)When MCU has data to be transmitted to SOC, the INIB interrupt output of 941 can be configured through 948 interrupt, so that 948 and 941 can cooperate to inform SOC to read data

    To achieve the above functions, which registers of 948 need to be configured and how to configure them.

    The customer is a newbs, hope to explain in detail. Thank you in advance

  • 0 in reply to Amy Luo
    TI__Mastermind 19720 points

    Hi Amy,

    Why is your customer not using the SPI interface on the 941 and 948? The SPI sounds like a better fit than I2C for your customers.

    "If the system does require master-slave operation in both directions across the BCC, some method of communication must be used to ensure only one direction of operation occurs at any time. The communication method could include using available R/W registers in the deserializer to allow masters to communicate with each other to pass control between the two masters." 

    "When MCU has data to be transmitted to SOC, the INIB interrupt output of 941 can be configured through 948 interrupt, so that 948 and 941 can cooperate to inform SOC to read data"

    You have a way to tell the SOC that it needs to be in I2C slave mode, but you need a way to tell the MCU to be in slave mode, or be in slave mode by default.

    You need to set the I2C_PASS_THROUGH_ALL bit to 1.

    Regards,

    Michael W.

  • 0 in reply to Michael.Walker
    TI__Expert 6895 points

    Michael,

    Appreciated. 

    There are two more questions
    1. 948 is connected with the display screen through LVDS. When SOC transmits video signal to 948, what configuration should be made for 948 to transmit video signal to display screen?
    2. When the screen needs to be tested, 948 is required to control the display screen to display red, green and blue. How to configure it?

  • 0 in reply to Amy Luo
    TI__Mastermind 37040 points

    Hi Amy,

    Thank you for reaching out to us. Were you able to get your setup up and running? if not, I would suggest you to perform the following items to enable video patgen.

    1. Are you using customer board or TIEVM? If you are using TIEVM, you should be able to connect the EVM to ALP, then you can enable the patgen to test your 948 device to display. If you are using customer board, please refer to patgen registers to configure patgen video output.
    2. Once you successfully outputted the video patgen, then you can also test the 947 patgen to confirm whether you are getting the video across the link.

    Normally, you do not need to configure anything on 948 besides strap the hardware to the correct of your desired setting. Do you what is your timing resolution?

    Aaron