MC68HC908MR8CFA Freescale Semiconductor, MC68HC908MR8CFA Datasheet - Page 118

• Manufacturer Part Number: MC68HC908MR8CFA
• Description: IC MCU 8K FLASH 8MHZ PWM 32-LQFP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC68HC908MR8CFA

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: SCI
• Peripherals: LVD, POR, PWM
• Number Of I /o: 16
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 7x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

Clock Generator Module (CGM)
8.4.2.2 Acquisition and Tracking Modes
8.4.2.3 Manual and Automatic PLL Bandwidth Modes
Technical Data
118
The PLL filter is manually or automatically configurable into one of two
operating modes:
The PLL can change the bandwidth or operational mode of the loop filter
manually or automatically.
In automatic bandwidth control mode (AUTO = 1), the lock detector
automatically switches between acquisition and tracking modes.
Automatic bandwidth control mode also is used to determine when the
VCO clock, CGMVCLK, is safe to use as the source for the base clock,
CGMOUT
are enabled, the software can wait for a PLL interrupt request and then
check the LOCK bit. If interrupts are disabled, software can poll the
LOCK bit continuously (during PLL startup, usually) or at periodic
intervals. In either case, when the LOCK bit is set, the VCO clock is safe
to use as the source for the base clock (see
Circuit). If the VCO is selected as the source for the base clock and the
LOCK bit is clear, the PLL has suffered a severe noise hit and the
software must take appropriate action, depending on the application.
See
•
•
8.7 Interrupts
Acquisition mode — In acquisition mode, the filter can make large
frequency corrections to the VCO. This mode is used at PLL
startup or when the PLL has suffered a severe noise hit and the
VCO frequency is far off the desired frequency. When in
acquisition mode, the ACQ bit is clear in the PLL bandwidth control
register. See
Tracking mode — In tracking mode, the filter makes only small
corrections to the frequency of the VCO. PLL jitter is much lower
in tracking mode, but the response to noise is also slower. The
PLL enters tracking mode when the VCO frequency is nearly
correct, such as when the PLL is selected as the base clock
source. The PLL is automatically in tracking mode when not in
acquisition mode or when the ACQ bit is set. See
Clock Selector
Clock Generator Module (CGM)
(8.6.2 PLL Bandwidth Control
8.6.2 PLL Bandwidth Control
for information and precautions on using interrupts.
Circuit.
Register). If PLL interrupts
8.4.3 Base Clock Selector
MC68HC908MR8 — Rev 4.1
Freescale Semiconductor
Register.
8.4.3 Base