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DS90UB947-Q1: IIC communication fails

kevin.huang_FJXM
Expert 2925 points
Part Number: DS90UB947-Q1

hi teams:

1. Perform software reset (register 0x01 writes 0x03), and IC communication is normal under 3.3V system voltage

2. Perform software reset (write 0x01 to 0x03), and IIC communication fails under 1.8V system voltage

Supplement: Other conditions are the same, only the difference is between 3.3V and 1.8V

Question: Please help find out what causes the problem? What is the solution?

  • 0
    TI__Guru** 103215 points

    Kevin,

    This is a known issue with the device which is documented in the datasheet register 0x15:

    Issuing digital reset using 0x01 will cause the I2C voltage to revert to 3.3V always. There is no way to avoid this so if you are using 1.8V I2C, then you must not issue digital reset with 0x01[1] or 0x01[0]

    Best Regards,

    Casey