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DS90UB927Q-Q1: I2C Master Through FPD-LINK III DS90UB927Q-Q1 Links With FPD-LINK III DS90UB948-Q1 To I2C Slave Touch Controller Redundancy Design / Pin Configuration

Bright Wang40
Intellectual 540 points
Part Number: DS90UB927Q-Q1
Other Parts Discussed in Thread: DS90UB948-Q1

We Have An Automotive Head Unit Design Consists Of 2 Units : Display Touch Combo Module Device And Main Head Unit ECU As Below

We Need Your Helps To Confirm Our Questions From Our Block Diagram. As You See From Our Block Diagram We Use Both Of Microcontroller ( In Block Diagram µC ) And Application Processor ( In Block Diagram MPU ) To Prevent Touch Control Function From Failure. Our Design Is Due To Functional Safety Requirement So We Use Another Logic I2C Bus Multiplexer As Switch And Keep Either Of MPU And µC For An Redundancy.  And As You See From Our Block Diagram The ECU Side Use DS90UB927Q-Q1 Serializer LINK Through A Cable Wire To Connect Display Touch Combo Module Device. In Our Case We Use I2C And BCC To Get I2C Data From Touch Controller. Our Questions Are:

1. For Redundancy Design The MUX Switch Seems Necessary But May Cause A Latency?

2. Does TI Have Suitable I2C Bus Selector / Bus MUX Switch For Design Case Like Ours (The Recommended Parts Shall Be AEC-Q100) ?

3. From Datasheet Of DS90UB927Q-Q1 Pin 9 / 10 / 11 Can Be Used For Remote I2C Through FPD-LINK. But We Don't Really Understand What Is Pin 18 PDB For? 

4. To Link DS90UB927Q-Q1 We've Checked The Datasheet Of Deserializer Side DS90UB948-Q1. The Dual FPD-LINK III Deserializer Device Only Has 1 Set I2C Pin 45 / 46 / 47. Our Question Is Does The DS90UB48-Q1 Allow Multiple I2C Master?

  • 0
    TI__Mastermind 30515 points

    Bright,

    The I2C is based on the shared bus (SCL, SDA), both uc and mpu can be connected to this bus.

    1. it is dependent on how is your redundancy design. If only one master is available in one time, the i2c mux can be removed. regarding the latency, it is not important spec. for this application.

    2. If you need use i2c mux, you can select one analog mux device for it.

    3. regarding the i2c pins of UB927, and its application, please check the i2c description in d/s, also please refer to app. note • I2C Communication Over FPD-Link III with Bidirectional Control Channel, SNLA131. regarding the pin PDB, it is power down mode input pin, you can refer to page4 of ub927 d/s.

    4.what is your "multiple I2C master"? for FPD-Link, only one I2C is transmitted in the back channel / forward channel. In your application, ONLY one master I2C is available in one time. 

    regards,

    Steven