I managed to read from an MCP4725 using I2C. In the second byte below, the POR value it gives me is '1' (the whole byte is 11000000)

I2C POR 2nd byte

I know that if RDY/BSY = 1, it means the device is ready to write its EEPROM.

When does POR = 0? What does it mean if POR = 1?

The datasheet gives no information about the value of POR. I think that POR = 1 when the IC's power is >2V and POR = 0 when IC's power is <2V. (But if that is the case, giving me the POR value has no meaning)


Based on the below section of the datasheet, since there is a "after POR" state, I think POR=1 means that the device has "completely woken up from its power-up/reset state and its ready to receive commands".


Since after the reset, the device loads the data from EEPROM to the register (to output its analog value,) this takes some time, and while POR = 0, this event is still taking place.

Am I right?

  • 1
    \$\begingroup\$ The device can be reset by two independent events: (a) by POR or (b) by I2C General Call Reset Command. - might it inform you what the event was that caused it? \$\endgroup\$
    – Andy aka
    Apr 6, 2021 at 13:09
  • \$\begingroup\$ Well, I did not do the General Call reset, so the Power was the one that Resetted the device. Hmm If I use the general call reset, will POR be 0 after that? I will try that. \$\endgroup\$ Apr 6, 2021 at 13:13
  • \$\begingroup\$ It's worth a shot. \$\endgroup\$
    – Andy aka
    Apr 6, 2021 at 13:13


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.