![](http://datasheet.mmic.net.cn/370000/P9S12XEP100J1VVLR_datasheet_16728329/P9S12XEP100J1VVLR_486.png)
Chapter 11 S12XE Clocks and Reset Generator (S12XECRGV1) Block Description
MC9S12XE-Family Reference Manual , Rev. 1.07
486
Freescale Semiconductor
11.3.2.7
S12XECRG IPLL Control Register (PLLCTL)
This register controls the IPLL functionality.
Read: Anytime
Write: Refer to each bit for individual write conditions
1
RTIWAI
RTI Stops in Wait Mode Bit
Write: Anytime
0 RTI keeps running in Wait Mode.
1 RTI stops and initializes the RTI dividers whenever the part goes into Wait Mode.
COP Stops in Wait Mode Bit
Normal modes: Write once
Special modes: Write anytime
0 COP keeps running in Wait Mode.
1 COP stops and initializes the COP counter whenever the part goes into Wait Mode.
0
COPWAI
Module Base + 0x0006
7
6
5
4
3
2
1
0
R
CME
PLLON
FM1
FM0
FSTWKP
PRE
PCE
SCME
W
Reset
1
1
0
0
0
0
0
1
Figure 11-9. S12XECRG IPLL Control Register (PLLCTL)
Table 11-6. PLLCTL Field Descriptions
Field
Description
7
CME
Clock Monitor Enable Bit
— CME enables the clock monitor. Write anytime except when SCM = 1.
0 Clock monitor is disabled.
1 Clock monitor is enabled. Slow or stopped clocks will cause a clock monitor reset sequence or Self Clock
Mode.
Note:
Operating with CME=0 will not detect any loss of clock. In case of poor clock quality this could cause
unpredictable operation of the MCU!
In Stop Mode (PSTP=0) the clock monitor is disabled independently of the CME bit setting and any loss
of external clock will not be detected.
Also after wake-up from stop mode (PSTP = 0) with fast wake-up enabled (FSTWKP = 1) the clock monitor
is disabled independently of the CME bit setting and any loss of external clock will not be detected.
6
PLLON
Phase Lock Loop On Bit
— PLLON turns on the IPLL circuitry. In Self Clock Mode, the IPLL is turned on, but
the PLLON bit reads the last written value. Write anytime except when PLLSEL = 1.
0 IPLL is turned off.
1 IPLL is turned on.
Table 11-5. CLKSEL Field Descriptions (continued)
Field
Description