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DS90UH949 I2C access of Port_1 register

Martin Langbein
Prodigy 60 points
Other Parts Discussed in Thread: ALP

Hello,

I'm developing test-equipment and need to set/read  the d_gpios over i2c of the ds90uh949 evalboard. It is possible to set the port_sel register correct (I was able to check the value in ALP) but it seems it has no effect. I set/read alway the port_0 values

Is it possible that port1_register are not reachable over i2c?
Is the chip to old and a newer generation of the chip would solve my issue?

Best regards

Martin

  • 0
    TI__Genius 14015 points

    Hi Martin,

    Are you talking to the 949 locally or remotely (through the deserializer)? What value are you setting in register 0x1E to choose port 0 or port 1? 

    There are two ways to access port 1 registers. Either set 0x1E to 0x02 (so PORT1SEL is set and PORT0SEL is cleared), or by enabling the secondary I2C address by writing 0x1E to 0x04. The secondary I2C address is located at N+1 (7-bit), so if the I2C address is 0x0C (0x18 8-bit), the N+1 would be 0x0D (0x1A 8-bit). When the GPIO registers are accessed via the original I2C address, the GPIO pins would be controlled. When the same registers are accessed via the new N+1 address, the D_GPIO registers would be controlled.

    Thanks,
    Jason

  • 0 in reply to Jason Blackman
    Prodigy 60 points
    Thank you for the fast reply.
    I'm sorry not to mention this earlier: I access the ds90uh949 remote from the deserializer ds90uh948.
    Could this cause issues accessing the d_gpio register?

    Locally on the 949 i am able to modify the D_GPIO(with ALP).

    Thank you,
    Martin