Erich Styger writes, “This tutorial is about how to use the NXP MCUXpresso Clock configuration and configure the board to the maximum clock frequency of 120 MHz. The same steps apply to many other boards, including the FRDM-K22F one. The tinyK22 has the K22FN512 ARM Cortex-M4F on it which runs up to 120 MHz. It is the same processor as the one on the FRDM-K22F.”
More details at mcuoneclipse.com.