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DS90UB948-Q1: Regarding the issue of DS90UB948 client reporting host and screen addressing errors

liu billy
Intellectual 560 points
Part Number: DS90UB948-Q1

Tool/software:

Dear  

    1)The deserializer address read by the host is 0x3f, but the address set by our hardware is 0x34. So, under what circumstances will this address change? 

Resistance adopts 1% accuracy

2) The following is the address of IIC in the specification sheet, and there is no address 0x3f.

We will investigate the situation as follows:
1. We have checked the power on timing of the 948 terminal and it is consistent with the requirements of the specification sheet.
2. Excluded voltage fluctuations caused by IDX's voltage division.
May I ask if there are any other circumstances that could cause a change in the address? For example, is there a possibility of rewriting the display screen address inside the deserializer, or are there any possible ways to rewrite this address on the adder end?

  • 0 in reply to liu billy
    TI__Mastermind 33365 points

    Hello,

    The 948's I2C address is set at power-up. The device will measure the voltage at the IDx pin and set the I2C address based on the table shown in the datasheet.

    There is no address 0x3F so I am curious as to whether the host is actually reading the correct address. Can you tell me what serializer you are using and if you are enabling I2C pass-through on the serializer?

    A register dump of the serializer and a screenshot of the host reading the 0x3F address would be helpful.

    Best,

    Jack

  • 0 in reply to Jack Scherlag
    Intellectual 560 points

    hello  Jack

    The serializer we use is ds90ub941as and enable I2C pass-through during the initialization of 941, and then obtained the 948 i2c address by reading the 941 0x06 register.
    we have no register dump or screenshot because the problem occurred in the customer's car

  • 0 in reply to liu billy
    TI__Mastermind 33365 points

    Hi Billy,

    We will need to clarify some points. I cannot tell if you are saying if the I2C address determined from this register is 0x3F or the register readback is 0x3F. If you see the register description below, the 7-bit I2C address is available at bit field [7:1]. Bit 0 can be used to overwrite the deserializer IDx selection.

    • Is the exact value read back by 941 register 0x6 = 0x3F?
    • Is the exact value read back by 941 register 0x6 = 0x7E?

    Best,

    Jack