While programming PLL on ADSP-214xx processors, it is must that the user take care of using the workaround of the anomaly#15000020. For more details on the workaround, please refer to the corresponding anomaly sheet. For example, ADSP-2146x anomaly sheet is available at the link below:
To generate the correct PLL programming code automatically with VisualDSP++, one can as well use the plugin "Expert Code generator" provided with the application note EE-322. It is available at the link below:
http://www.analog.com/media/en/technical-documentation/application-notes/EE-322rev5.pdf