I'm still discovering the K20 chip using the Tower K20 demo kit with the demo_gpio project supplied by freescale.
I have set a PIT as described in this earlier topic: https://community.freescale.com/thread/320172
I've left all the MCG config as is in the demo project.
the maximum tick frequency I can get with the PIT is around 2MHz, although the mcg_clk_hz is 72.000.000 (= core_clk)
Is this normal? I thought the max freq achievable with PIT should be half the core clock.