ADT7470 GPIO Status

Dear Sir,

      The ADT7470 Table 50. show "When GPIO is configured as an output, these bits are read/write. Setting these bits asserts the GPIO output. (Asserted can be high or low depending on the setting of GPIO4 polarity.)". We run below setting:

  1. Register 0x7F write "0x02" ==> set PWM3 as GPIO
  2. Register 0x80 write "0x0C" ==> set GPIO3 as output active high
  3. Register 0x81 write "0x0C" than 0x4C
  4. Register 0x81 write "0x0C"

But GPIO 3 ( PWM3 pin 8 ) level don't have any change (always high level) and Register 0x81 always read equal to "0x0C" at each step. Please help to check this issue. Thanks!


 
 
 
 





  • 0
    •  Analog Employees 
    on Aug 20, 2015 1:48 PM

    Hi,

    I see by writing alternatively 0x4C and 0x0C you expect to see the PWM3, toggling because you are writing to bit 6, however why setting bits 2&3? Default values appear to be 00 and this bits should be reserved. Have you tried reading the registers after every write just to make sure you are actually writting what you were expecting? I mean for instance:

    • Register 0x7F write "0x02" ==> set PWM3 as GPIO
      • Read Register 0x7F
    • Register 0x80 write "0x0C" ==> set GPIO3 as output active high
      • read Register 0x80
    • Register 0x81 write "0x0C"
      • read regster 0x81
    • Register 0x81, write 0x4C
      • read register 0x81
    • Register 0x81 write "0x0C"
      • read register 0x81

    Also, would it be possible to share your schematic so I could check how are you connecting your hardware to that output?


    Regards,

    Lluis.

  • Dear Lluis,

        I use ADI's EVB to test. Please refer attached file is follow your suggest result. The Register 0x81 value still keep "0x0C". Please help to check. Thanks!

  • 0
    •  Analog Employees 
    on Aug 21, 2015 12:18 PM

    Hi Sam,

    If you are using the eval board, you will need to connect first the 12V power supply. In any case, I replicated what you are doing and it seems that this register cannot be read/written. We might need some time to review the software code or further evaluate the part itself. Thanks for pointing it out.

    However, we could workaround it at the moment: you can control the GPIO outputs by modifying its polarity. I monitored the 4 GPIO (with the 12V supply connected) and did the following sequence:

    -Enable the desired GPIOs on register 0x7F

    -Set the desired GPIOs as outputs on register 0x80

    -Toggle the GPIO desired by changing its polarity on register 0x80(as I was monitoring the outputs I could easily see the outputs level changing, for GPIO1 and GPIO2 you can also observe whether the fan is ON or OFF)

    This can be done more easily by using the GPIO configuration window, clicking on the third icon from the right hand side. Please note you will need to allow a short delay since the button is pressed until the output voltage level changes.

    I hope this works, and apologies for the inconveniences.

    Best regards,

    Lluis.

  • Dear Lluis,

           I had connect the 12V power supply. So, the register 0x81 just read only. Right?

    Best regards,

    Sam Shyu

  • 0
    •  Analog Employees 
    on Aug 2, 2018 3:09 PM
    This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

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    EZ Admin