Chapter 9 Clocks and Reset Generator (CRGV4) Block Description
Freescale Semiconductor
MC9S12C-Family / MC9S12GC-Family
261
Rev 01.24
9.3.2.7
CRG PLL Control Register (PLLCTL)
This register controls the PLL functionality.
Read: anytime
Write: refer to each bit for individual write conditions
2
CWAI
Core Stops in Wait Mode Bit
— Write: anytime
0 Core clock keeps running in wait mode.
1 Core clock stops in wait mode.
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.
0
COPWAI
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 dividers whenever the part goes into wait mode.
Module Base + 0x0006
7
6
5
4
3
2
1
0
R
CME
PLLON
AUTO
ACQ
0
PRE
PCE
SCME
W
Reset
1
1
1
1
0
0
0
1
= Unimplemented or Reserved
Figure 9-10. CRG PLL Control Register (PLLCTL)
Table 9-5. 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.
Note:
In Stop Mode (PSTP = 0) the clock monitor is disabled independently of the CME bit setting and any loss
of clock will not be detected.
6
PLLON
Phase Lock Loop On Bit
— PLLON turns on the PLL circuitry. In self-clock mode, the PLL is turned on, but the
PLLON bit reads the last latched value. Write anytime except when PLLSEL = 1.
0 PLL is turned off.
1 PLL is turned on. If AUTO bit is set, the PLL will lock automatically.
Table 9-4. CLKSEL Field Descriptions (continued)
Field
Description
Summary of Contents for MC9S12C Family
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