Datasheet

14.2 Features
Features of the RTC module include:
• 16-bit up-counter
• 16-bit modulo match limit
• Software controllable periodic interrupt on match
• Software selectable clock sources for input to prescaler with programmable 16 bit
prescaler
• XOSC 32.678KHz nominal.
• LPO (~1 kHz)
• Bus clock
14.2.1 Modes of operation
This section defines the RTC operation in stop, wait, and background debug modes.
14.2.1.1 Wait mode
The RTC continues to run in wait mode if enabled before executing the WAIT
instruction. Therefore, the RTC can be used to bring the MCU out of wait mode if the
real-time interrupt is enabled. For lowest possible current consumption, the RTC must be
stopped by software if not needed as an interrupt source during wait mode.
14.2.1.2 Stop modes
The RTC continues to run in stop3 mode if the RTC is enabled before executing the
STOP instruction. Therefore, the RTC can be used to bring the MCU out of stop modes
with no external components, if the real-time interrupt is enabled.
14.2.2 Block diagram
The block diagram for the RTC module is shown in the following figure.
Features
MC9S08PA60 Reference Manual, Rev. 1, 9/2012
394 Freescale Semiconductor, Inc.