English
Language : 

MC68HC08AZ32A Datasheet, PDF (124/456 Pages) Motorola, Inc – HCMOS Microcontroller Unit
Freescale Semiconductor, Inc.
Clock Generator Module (CGM)
Technical Data
124
These conditions apply when the PLL is in automatic bandwidth control
mode:
• The ACQ bit (See 8.6.2 PLL Bandwidth Control Register.) is a
read-only indicator of the mode of the filter. See Acquisition and
Tracking Modes on page 123.
• The ACQ bit is set when the VCO frequency is within a certain
tolerance, ∆trk, and is cleared when the VCO frequency is out of a
certain tolerance, ∆unt. See Electrical Specifications on page 423.
• The LOCK bit is a read-only indicator of the locked state of the
PLL.
• The LOCK bit is set when the VCO frequency is within a certain
tolerance, ∆Lock, and is cleared when the VCO frequency is out of a
certain tolerance, ∆unl. See Electrical Specifications on page 423.
• CPU interrupts can occur if enabled (PLLIE = 1) when the PLL’s
lock condition changes, toggling the LOCK bit. See PLL Control
Register on page 131.
The PLL also can operate in manual mode (AUTO = 0). Manual mode is
used by systems that do not require an indicator of the lock condition for
proper operation. Such systems typically operate well below fbusmax and
require fast startup. The following conditions apply when in manual
mode:
• ACQ is a writable control bit that controls the mode of the filter.
Before turning on the PLL in manual mode, the ACQ bit must be
clear.
• Before entering tracking mode (ACQ = 1), software must wait a
given time, tacq (see Electrical Specifications on page 423), after
turning on the PLL by setting PLLON in the PLL control register
(PCTL).
• Software must wait a given time, tal, after entering tracking mode
before selecting the PLL as the clock source to CGMOUT
(BCS = 1).
• The LOCK bit is disabled.
• CPU interrupts from the CGM are disabled.
MC68HC08AZ32A — Rev 1.0
Clock Generator Module (CGM)
For More Information On This Product,
Go to: www.freescale.com
MOTOROLA