27.4.2 Clocks

Two synchronous clocks are used by the NVMCTRL. One is provided by the AHB bus (CLK_NVMCTRL_AHB) and the other is provided by the APB bus (CLK_NVMCTRL_APB). When changing the AHB bus frequency, the user must ensure that the NVM Controller is configured with the proper number of wait states. Refer to the Electrical Characteristics for the exact number of wait states to be used for a particular frequency range. Automatic wait state generation can be use by setting the Auto Wait State bit in the Control A register (NVMCTRL.CTRLA.AUTOWS). Alternatively a custom programmable number of wait states can be set by writing the NVM Read Wait State bits (NVMCTRL.CTRLA.RWS) to optimize performance.