K60P100M100SF2RM Datasheet, PDF (1110/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

Register definition
During chip power-down, RTC is powered from the backup power supply (VBAT) and is
electrically isolated from the rest of the chip but continues to increment the time counter
(if enabled) and retain the state of the RTC registers. The RTC registers are not
accessible.
During chip power-up, RTC remains powered from the backup power supply (VBAT).
All RTC registers are accessible by software and all functions are operational. If enabled,
the 32.768 kHz clock can be supplied to the rest of the chip.
43.1.3 RTC signal descriptions
Table 43-1. RTC signal descriptions
Signal
Description
I/O
EXTAL32
32.768 kHz oscillator input
I
XTAL32
32.768 kHz oscillator output
O
RTC_CLKOUT
1Hz square-wave output
O
RTC_WAKEUP
Wakeup for external device
O
43.1.3.1 RTC clock output
The clock to the seconds counter is available on the RTC_CLKOUT signal. It is a 1Hz
square wave output.
43.1.3.2 RTC wakeup pin
The RTC wakeup pin is an open drain, active low, output that allows the RTC to wakeup
the chip via an external component. The wakeup pin asserts when the wakeup pin enable
is set, the RTC interrupt is asserted and the chip is powered down. The wakeup pin does
not assert from the RTC seconds interrupt.
The wakeup pin is optional and may not be implemented on all devices.
43.2 Register definition
All registers must be accessed using 32-bit writes and all register accesses incur three
wait states.
1110
K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc.