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INA219: INA219 Calibration Register

Joel Krawczyk
Prodigy 30 points
Part Number: INA219

Hello,

The data sheet for the INA219 shows that Bit 0 (FS0) in the calibration register is not used and is read only.

Do I need to shift the calibration value to the left one bit before I write it to the register?

Example:

Lets say I want to use a calibration value of decimal 14300.

Should I write 37DCh to the register?

or should I shift the bits to the left to avoid using the FS0 bit and write 6FB8h to the register?

Thanks!

  • 0
    TI__Mastermind 32395 points
    Hey Joel,

    You should write the 37DCh value to the calibration register. When you write to the calibration register (05h), the last bit in the LSB will always be ignored by the part, thus leaving the FS0 bit of calibration register as a 0. Basically, whatever value you write to the register it will make the last bit a 0.

    When you read the calibration register, you read all 16 bits and thus you would read back 37DCh if this value was initially written to register. You can confirm this on page 26 of INA219 datasheet where 5000h was the calculated calibration value, 5000h was written to calibration register, and 5000h is read back from calibration register.

    Sincerely,
    Peter Iliya
    Current Sensing Applications