by enabling the chip-specific RTC clock gate control bit. The RTC interrupt can be used
to wakeup the chip from any low-power mode. If the RTC wakeup pin is enabled and the
chip is powered down, the RTC interrupt will cause the wakeup pin to assert.
The optional RTC seconds interrupt is an edge-sensitive interrupt with a dedicated
interrupt vector that is generated once a second and requires no software overhead (there
is no corresponding status flag to clear). It is enabled in the RTC by the time seconds
interrupt enable bit and enabled at the chip level by setting the chip-specific RTC clock
gate control bit. The RTC seconds interrupt does not cause the RTC wakeup pin to assert.
This interrupt is optional and may not be implemented on all devices.
Functional description
K22F Sub-Family Reference Manual , Rev. 3, 7/2014
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Freescale Semiconductor, Inc.