The TMS320VC5506/C5507/C5509A USB peripherals can be clocked from either the USB apll or the
USB DPLL. Since the apll is inherently more noise tolerant and has less long-term jitter than the DPLL,
it is recommended that you switch to it for any USB operations.
This document describes how to switch to and program the unisersal serial bus (USB)
analog phase-locked loop (apll) on the C5506/C5507/C5509A devices. Example
assembly programs for programming and switching to and from the apll are also
provided in the attached zip file. It is assumed that the reader is familiar with the use
and operation of the C5506/C5507/C5509A USB digital phase-locked loop (DPLL) and
C55x™ Digital Signal Processor (DSP) IDLE procedures.
