mc68hc908mr8 Freescale Semiconductor, Inc, mc68hc908mr8 Datasheet - Page 124

• Manufacturer Part Number: mc68hc908mr8
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Clock Generator Module (CGM)
8.5.4 PLL Analog Power Pin (V
8.5.5 Oscillator Enable Signal (SIMOSCEN)
8.5.6 Crystal Output Frequency Signal (CGMXCLK)
8.5.7 CGM Base Clock Output (CGMOUT)
8.5.8 CGM CPU Interrupt (CGMINT)
Technical Data
124
NOTE:
V
V
Route V
capacitors as close as possible to the package.
The SIMOSCEN signal comes from the system integration module (SIM)
and enables the oscillator and PLL.
CGMXCLK is the crystal oscillator output signal. It runs at the full speed
of the crystal (f
Figure 8-3
OSC2 and may not represent the actual circuitry. The duty cycle of
CGMXCLK is unknown and may depend on the crystal and other
external factors. Also, the frequency and amplitude of CGMXCLK can be
unstable at startup.
CGMOUT is the clock output of the CGM. This signal goes to the SIM,
which generates the MCU clocks. CGMOUT is a 50 percent duty cycle
clock running at twice the bus frequency. CGMOUT is software
programmable to be either the oscillator output, CGMXCLK, divided by
two or the VCO clock, CGMVCLK, divided by two.
CGMINT is the interrupt signal generated by the PLL lock detector.
DDA
DDA
is a power pin used by the analog portions of the PLL. Connect the
pin to the same voltage potential as the V
DDA
DDA
Clock Generator Module (CGM)
shows only the logical relation of CGMXCLK to OSC1 and
carefully for maximum noise immunity and place bypass
)
XCLK
) and comes directly from the crystal oscillator circuit.
MC68HC908MR8 — Rev 4.1
DD
Freescale Semiconductor
pin.