Information

System Configuration
MPC8308 PowerQUICC II Pro Processor Reference Manual, Rev. 1
5-40 Freescale Semiconductor
register (RTCTR) is used to enable or disable the various timer functions. The real time counter event
register (RTEVR) is used to report the interrupt source. The RTC counter is initialized by software and can
be disabled if needed.
Figure 5-27 shows the RTC block diagram.
Figure 5-27. RTC Block Diagram
5.4.2 Features
The key features of the RTC module include the following:
• 32-bit RTC counter
— Increments for every one second
— Can be initialized by software to a specific initial count value
• An alarm function with programmable and maskable alarm interrupt
• Programmable and maskable every second interrupt
• Two possible clock sources
— External RTC clock—RTC_PIT_CLOCK
— CSB bus clock
• RTC function can be disabled, if required
5.4.3 Assumptions
RTC does not reset during Power On Reset or HRESET and needs to be explicitly reset by software. To
reset RTC, set the RTCCR[RESET_RTC] bit.
5.4.4 Modes of operation
The RTC unit can operate in the following modes:
• RTC enable/disable mode
• RTC every-second interrupt enable/disable mode
• RTC alarm interrupt enable/disable mode
• RTC internal/external input clock mode
Real Time
Second
Interrupt
RTC Input
Clock Module
Register Interface
Clock
CSB Bus
Clock
Alarm
Interrupt