mc68hc912dg128 Freescale Semiconductor, Inc, mc68hc912dg128 Datasheet - Page 157

• Manufacturer Part Number: mc68hc912dg128
• Description: M68hc12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

11.4 Phase-Locked Loop (PLL)
MC68HC912DG128 — Rev 3.0
MOTOROLA
INT ECLK
CANCLK
T1CLK
T2CLK
T3CLK
T4CLK
PCLK
XCLK
NOTE:
The phase-locked loop (PLL) of the 68HC(9)12DG128 is designed for
robust operation in an Automotive environment. The allowed PLL crystal
or ceramic resonator reference of 0.5 to 8MHz is selected for the wide
availability of components with good stability over the automotive
temperature range. Please refer to
Chains
When selecting a crystal, it is recommended to use one with the lowest
possible frequency in order to minimise EMC emissions.
An oscillator design with reduced power consumption allows for slow
wait operation with a typical power supply current less than a milli-
ampere. The PLL circuitry can be bypassed when the VDDPLL supply is
at VSS level. In this case, the PLL module is powered down and the
oscillator output transistor has a stronger transconductance for improved
drive of higher frequency resonators (as the crystal frequency needs to
be twice the maximum bus frequency). Refer to
Signal
Figure 11-1. Internal Clock Relationships
Freescale Semiconductor, Inc.
For More Information On This Product,
Descriptions.
for an overview of system clocks.
Go to: www.freescale.com
Clock Functions
Figure 11-6
Figure 3-3
in section
Phase-Locked Loop (PLL)
Clock Divider
in
Clock Functions
Technical Data
Pinout and
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