Real-Time Clock (RTC/API)
MPC5606S Microcontroller Reference Manual, Rev. 7
Freescale Semiconductor 1095
Chapter 32
Real-Time Clock (RTC/API)
32.1 Overview
The RTC is a free running counter used for timekeeping applications. The RTC may be configured to
generate an interrupt at a predefined interval independent of the mode of operation (run mode or
low-power mode). If in a low-power mode when the RTC interval is reached, the RTC will first generate
a wakeup and then assert the interrupt request. The RTC also supports an autonomous periodic interrupt
(API) function used to generate a periodic wakeup request to exit a low-power mode or an interrupt
request.
32.2 Features
Features of the RTC include:
• Four selectable counter clock sources
— 4–16 MHz FXOSC
— 128 kHz SIRC
— 32 KHz SXOSC
— 16 MHz FIRC
• Optional 512 prescaler and optional 32 prescaler
• 32-bit counter
— supports times up to 1.5 months with 1 ms resolution
— runs in all modes of operation
— reset when disabled by software and by POR
• 12-bit compare value to support interrupt intervals of 1 s up to greater than 1 hr with 1 s resolution
• RTC compare value changeable while counter is running
• RTC status and control register are reset only by POR
• Autonomous periodic interrupt (API)
— 10-bit compare value to support wakeup intervals of 1.0 ms to 1 s
— compare value changeable while counter is running
• Configurable interrupt for RTC match, API match, and RTC rollover
• Configurable wakeup event for RTC match, API match, and RTC rollover
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