XC908AS60ACFU Motorola Semiconductor Products, XC908AS60ACFU Datasheet - Page 186

• Manufacturer Part Number: XC908AS60ACFU
• Description: MC68HC908AZ60A, MC68HC908AS60A Hcmos Microcontroller Unit Technical Data
• Manufacturer: Motorola Semiconductor Products

Clock Generator Module (CGM)
Technical Data
186
AUTO — Automatic Bandwidth Control Bit
LOCK — Lock Indicator Bit
ACQ — Acquisition Mode Bit
XLD — Crystal Loss Detect Bit
This read/write bit selects automatic or manual bandwidth control.
When initializing the PLL for manual operation (AUTO = 0), clear the
ACQ bit before turning on the PLL. Reset clears the AUTO bit.
When the AUTO bit is set, LOCK is a read-only bit that becomes set
when the VCO clock, CGMVCLK, is locked (running at the
programmed frequency). When the AUTO bit is clear, LOCK reads as
logic 0 and has no meaning. Reset clears the LOCK bit.
When the AUTO bit is set, ACQ is a read-only bit that indicates
whether the PLL is in acquisition mode or tracking mode. When the
AUTO bit is clear, ACQ is a read/write bit that controls whether the
PLL is in acquisition or tracking mode.
In automatic bandwidth control mode (AUTO = 1), the last-written
value from manual operation is stored in a temporary location and is
recovered when manual operation resumes. Reset clears this bit,
enabling acquisition mode.
When the VCO output, CGMVCLK, is driving CGMOUT, this
read/write bit can indicate whether the crystal reference frequency is
active or not.
1 = Automatic bandwidth control
0 = Manual bandwidth control
1 = VCO frequency correct or locked
0 = VCO frequency incorrect or unlocked
1 = Tracking mode
0 = Acquisition mode
1 = Crystal reference not active
0 = Crystal reference active
Clock Generator Module (CGM)
MC68HC908AZ60A — Rev 2.0
MOTOROLA