Looking at table 5.8 of the HMC PLL operating guide (http://www.analog.com/media/en/technical-documentation/user-guides/pll_operating_guide_rf_vcos.pdf ), the user is instructed to program values to various bits of register 6 that differ from the power on defaults without any explanation. e.g. bit 10 defaults to 0, but has the description "Program 1". Does this mean that the default values will not work and *must* be overridden for normal operation? Or, are the default values okay? Can you give me any indication as to what these bits do?