I want to manually control/configure an un-programmed PMIC with my micro over I2C, but having trouble doing so. Is there a minimum register setting that must be pre programmed to accomplish this.
Our datasheets contain a lot of useful information on the I2C interface. For example, the DA9063 datasheet has a few useful sections on how to interface with DA9063 over I2C and the DA9063 I2C interface registers. Section 18.104.22.168, titled 2-WIRE Communication on page 88, has a brief overview on how to interface with the DA9063 and a link to the register tables. The register table can be found in section A.4.2, Table 225, titled INTERFACE. This table alongside the GUI should be able to provide an example on how to interface with your PMIC over I2C.
Link to DA9063 Datasheet: