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DS90UB949-Q1EVM: Question about I2C with this part

Dimitri Petitjean
Prodigy 10 points
Part Number: DS90UB949-Q1EVM
Other Parts Discussed in Thread: DS90UB948-Q1, , ALP

Hello,

I had a few questions about the utilisation with the I2C on this serializer evaluation board with a DS90UB948-Q1 deserializer.

I wanted to know if with a quick-start configuration, it would be necessary for the upstream device to be connected with the DS90UB949-Q1EVM in USB and if it is necessary for it to send I2C data.

Also, is it necessary if I want to configure the registers for I2C, is it compulsory to use the ALP software for this type of configuration ?

Thank you very much for your answers. 

Best regards,

Dimitri Petitjean

  • 0
    TI__Expert 4160 points

    Hi Dimitri,

    Thank you for your questions!

    Could you clarify what is a quick-start configuration? Is this powering on the device?

    There is no bringup code/ I2C commands necessary for the 949 that the SOC needs to send to the 949 upon startup.

    You can connect the upstream device (laptop/computer/etc.) anytime. You do not need to have the evm plugged in to the your device using USB before power-up.

    ALP allows you to interface with the onboard I2C master MSP430 using a GUI. If you have your own master and disable the onboard MSP430 you could technically configure the registers using a different master without using ALP.

    Respectfully,

    WIlliam Y.

  • 0 in reply to William Yi
    Prodigy 10 points

    Hi, 

    Thank you for your answer. In the user guide of the DS90UB949-Q1EVM, there is a specification which indicates a quick-start configuration. I attach you a picture from the User Guide.

    I assume with your purpose that it is compulsory to plug the upstream SoC in USB when I want to send permanently pictures threw the HDMI connector of the SoC.

    So this I2C master is the one that send the I2C datas in the FPD-Link ? And it means that I don't have to send I2C data with the SoC thanks to this MSP430 ? If so, why do I have to connect the SoC with the board with USB ?

    Thank you very much.

    Best regards,

    Dimitri Petitjean

  • 0 in reply to Dimitri Petitjean
    TI__Expert 4160 points

    Hi Dimitri,

    Thank you for pointing out the quick start guide on the evm user manual. 

    Dimitri Petitjean said:
    I assume with your purpose that it is compulsory to plug the upstream SoC in USB when I want to send permanently pictures threw the HDMI connector of the SoC.

    I dont think I understand this question. Could you clarify what this means?

    Dimitri Petitjean said:
    So this I2C master is the one that send the I2C datas in the FPD-Link ? And it means that I don't have to send I2C data with the SoC thanks to this MSP430 ? If so, why do I have to connect the SoC with the board with USB ?

    Yes, the I2C master/MCU is the onboard MSP430. You can see it's schematic on page 36 of the evm user guide. It is the MCU of the system. You can think of it like a bridge that translates your commands from USB to I2C and sends it to the 949. You need to connect the MCU to your PC so that you can interface the MCU to give commands/access registers of the 949 using Analog Launch Pad. 

  • 0 in reply to William Yi
    Prodigy 10 points

    Hi again William,

    I think my question will be more simple to understand with this diagram : 

    This is the communication channel I am currently working on. My question is : do I have to connect the RPi in I2C with the DS90UB949-Q1EVM when I am sending datas threw the HDMI ?

    I don't know if it helps you but in fact I don't really understand the purpose of the I2C between the RPi and the EVM. So if it is compulsory I want to know if I have to create a script in the RPi to configure the EVM.

    Best regards,

    Dimitri Petitjean.

  • 0 in reply to Dimitri Petitjean
    TI__Expert 4160 points

    Hi Dimitri,

    Thank you for your question. I think this is much simpler than we are making it.

    No, you do not need the Rpi connected with the 949 after it has been configured. The I2C communication allows you to setup the registers on the 949 and 948 configurations.

    Once configured, you can disconnect the ALP and stop interfacing with the msp430 all together if you are just sending video data to the 949.

    Respectfully,

    William Y.

  • 0 in reply to William Yi
    Prodigy 10 points

    Hello William,

    Thanks again for your help. I just have two more questions about it and I will stop to bother you ^^. Do the 949 and 948 have a default I2C registers configuration and so it will not be compulsory to configure them to start a communication. Also, do I have to configure again the registers each time I restart the board or the configuration is saved ?

    Thank you very much.

    Best regards,

    Dimitri Petitjean

  • 0 in reply to Dimitri Petitjean
    TI__Expert 4160 points

    Hi Dimitri,

    Thank you for your questions!

    Yes, the 949 and 948 have default I2C register configurations. You can see the default register settings in the datasheet.

    If you powercycle the 949/948, it will return to the default register settings of the 949/948. You will need to reconfigure the registers upon startup. 

    Respectfully,

    William Y.

  • 0
    Prodigy 10 points

    Hello William !

    Thank you very much for your help !

    Best regards,

    Dimitri Petitjean