Systems and methods are disclosed herein to provide location determination capability and applications for an access point. During test mode, a phase comparator of the DLL receives a test clock in place of the reference clock and determines the phase difference between the test clock and the clock fed back to the DLL from a clock buffer tree. A therapeutic agent of choice becomes non-removable, permanently contained between the inner and outer layers. A staging register comprising a first output clock rate which is one-quarter its input clock rate and matches a DUT burst write frequency may be coupled to an input of the data selector.