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INA231EVM startup addressing

Other Parts Discussed in Thread: INA231EVM, INA231

I am using the Aardvark  i2c/SPI adapter to talk to the INA231EVM evaluate module.  The module is not responding to any i2c slave addresses. Is there startup or setup that are needed before I can talk to the module ?

  • Hi Turin,

    Just need to make sure that you are setting the address pins correct (hardware), matching your code and Table 7 on the datasheet.
  • The address pins are not modified from factory condition, I have ran thru all 128 address and the module did not response to any of them. The default address is 0x40. Attached is a trace of the clock and  data line - the top trace is using the SM_USB_DIG and it ack properly - the bottom trace is using the aavrd and it did not answer.  As you can see both are doing a write to the same slave address. The module did not pull the data line low to acknowledge the address when the aavrd release the line.

  • Hi Turin,

    Note that the USBDIG provide the power to the board, internally. When you disconnect the USB DIG and connect your I2C reader, are you applying power to the device?
  • Yes 5-volt power is being supplied on pin 6 and GND to pin 10 of the 10 pin connector the USBDIG use. The same way how the USBDIG is connected. On the cable I have only i2c SCL ( pin 1), i2c SDA (pin 3), 5 volt ( [in 6) and GND (pin 8). Since I am not using SPI none of the SPI pin or GPIO are connected.
  • Hi Turin,

    I tested the INA231EVM with the Aardvark I2C/SPI system and it all works great at 3.3V. Your problem is that you are running your system at 5V and the Aardvark I2C lines are limited to 3.3V.

    See screenshots of my reading to register 0x00 and Aardvark user's manual section where they specify the lines at 3.3V. If you change your supply to 3.3V you should be able to communicate with the INA231.