SLVUAW9C September 2016 – February 2020 UCD90320
The internal variables used by the UCD90320 are often scaled to take optimal advantage of the hardware’s native units such as ADC or DAC counts rather than volts or amperes. As a result, values that are written and read via PMBus must undergo mathematical translations. These translations, with their inherent quantization, may result in very slight differences between the setting that was written to the UCD90320 and the value that was later read back from it. This is normal and compliant, described in section 7.4 of the PMBus specification.
In some cases, a value written to the device may cause it to exceed the range of its internal variable. In some cases, the device reports this as an error; in other cases it saturates the variable at a safe value. In all cases, the value read back via the PMBus reflects as accurately as possible the internal variable actually being used by the UCD90320.