Chapter 18 Real-Time Counter With Calendar (RTCV2)
S12ZVHY/S12ZVHL Family Reference Manual Rev. 1.05
Freescale Semiconductor
653
After a reset, the write-protect mechanism is disabled, allowing the user set the time and date in the calen-
dar registers.
18.5.6 Load buffer register
Compensation circuit and modulo circiuit using buffered register, those two register are loaded from
RTCCCR and RTCMOD only when compensation completed.Write to RTCMOD and RTCCCR is
blocked when CDLC=1, to protect data is stable when load occurs.
Figure 18-13. Buffered register load sequence and CDLC
18.6
Initialization/Application Information
18.6.1 RTC Calibration
18.6.1.1 ThRev. 1.05e off chip calibration
The RTC output clock (CALCLK) can be output on the RTC_CAL pin. User can measure the clcok
frequency directly. Refer to Device spec on how to enable the CALCLK on RTC_CAL pin.
18.6.1.2 The on chip calibration
The CALCLK signal can be routed to an internal timer channel for on-chip measurement. At same time,
user need feed one high precision 1 Hz clock to the other timer input pin. The calibration software can then
take simultaneous measurements of both signals using the input capture function of the timer to calculate
RTC CLK
SECF
COMPF
RTCMOD
RTCMOD_buf
CDLC
RTCEN