Although performing a full configuration of the UCD9090A in a controlled test setup is recommended, there may be times in which it is required to update the configuration while the device is in an operating system. Updating the full configuration based on methods listed in Device Configuration and Programming section while the device is in an operating system can be challenging because these methods do not permit the device to operate as required by application during the programming. During described methods the GPIOs may not be in the desired states which can disable rails that provide power to the device. To overcome this, the device has the capability to allow full configuration update while still operating in normal mode.

Updating the full configuration while in normal mode consists of disabling data flash write protection, erasing the data flash, writing the data flash image and reset the device. It is not required to reset the device immediately but make note that the UCD9090A continues to operate based on previous configuration with fault logging disabled until reset. See Configuration Programming of UCD Devices, available from the Documentation & Help Center that can be selected from the Fusion GUI Help menu, for details. The data flash script file generated from Fusion Digital Power Designer software has all the required PMBus commands. This is the recommended method for production programming.