When changing a generic clock source by
writing to CLKCTRL.GEN, the generic clock must be disabled before being re-enabled with the
new clock source setting. This prevents glitches during the transition:
- 1.Write CLKCTRL.CLKEN=0
- 2.Assert that CLKCTRL.CLKEN reads
'0'
- 3.Change the source of the generic
clock by writing CLKCTRL.GEN
- 4.Re-enable the generic clock by
writing CLKCTRL.CLKEN=1