SNIU028D February 2016 – September 2020 UCD3138 , UCD3138064 , UCD3138064A , UCD3138128 , UCD3138A , UCD3138A64
The KP_OFF, KD_OFF, and KI_OFF bits disable these sections of the filter, and replace those values with a zero. They also clear any history to a zero where it is present (I and D). Note that the history values are loaded with a zero the next time the filter is triggered. Normally the EADC is triggered by a sample trigger signal from a DPWM module. When the EADC conversion is complete, the filter is triggered. The filter can also be triggered by writing a 1 to the FORCE_START bit in the FILTERCTRL register. If neither of these events happens, the history will not be reset. So if the DPWM is not running, the history will not be cleared. Even if the DPWM is running, writing a 1 followed by a 0 to the KD and KI_OFF bits will not always clear the history. It depends if the filter is triggered and run while the bits are 1. If a quick clear is desired, use the FILTERPRESET register instead.