S12ZVHY/S12ZVHL Family Reference Manual Rev. 1.05
Freescale Semiconductor
639
Chapter 18
Real-Time Counter With Calendar (RTCV2)
Table 18-1. Revision History
18.1
Introduction
The real-time counter (RTC) supports the calendar functions. It can also serve as a cyclical wake up from
low power modes, STOP and WAITs, without the need of external components. A frequency compensa-
tion mechanism is built into this RTC module to allow adjustments made to the RTC clock when a less
accurate crystal is used or to correct frequency shifts due to changing temperature. The 1-Hz clock that
drives the clock and calendar could make use of the built-in compensation mechanism for crystal fre-
quency error compensation so that the 1-Hz clock could be made more accurate than the frequency accu-
racy of the crystal that drive the module.
18.2
Features
Features of the RTC module include:
•
16-bit up-counter
•
Support both 4-16MHz OSC(OSCCLCK) and 32.768KHz OSC(OSCCLK_32K) input
•
Calendar Counter registers for:
— Second
— Minute
— Hour
•
Five periodic interrupts
•
Built-in compensation mechanism for frequency error compensation
18.2.1 Modes of Operation
This section defines the RTC operation in stop, wait and background debug modes.
Version
Number
Revision
Date
Sections Affected
Description of Changes
0.0
April 2011
All
• inital Draft
0.7
March 2011
All
• fix typo on 18.1,18.2,18.3.4,18.5.3,18.5.6,18.6.1.1
0.8
March 2011
All
• V2 spec,add clock source of IRCCLK,
,
0.9
March 2011
All
• fix typo according review
