
MC97F6108A User’s manual
7. Clock generator
75
7
Clock generator
As shown in Figure 23, a clock generator produces basic clock pulses which provide a system clock for
CPU and peripheral hardware.
It contains main frequency clock oscillator. The internal RC oscillator is only used as system clock. The
default system clock is internal RC Oscillator and the default division rate is one.
Default system clock is 16MHz INT-RC Oscillator. To stabilize the system internally, internal 8kHz WDT
oscillator for BIT, WDT and ports de-bounce on POR is recommended.
Oscillators in the clock generator are introduced in the followings:
Calibrated high internal RC oscillator (16MHz)
—
INTRC OSC/1 (16MHz, default system clock)
—
INTRC OSC/2 (8MHz)
—
INTRC OSC/4 (4MHz)
—
INTRC OSC/8 (2MHz)
7.1
Clock generator block diagram
In this section, a clock generator of MC97F6108A is described in a block diagram.
SCLK = fX
(Core, System, Peripheral)
SYSCK[1:0]
WDTRCON
BIT
clock
Stabilization
Time
Generation
WDTCK
BITWDTRC
fWDTRC
System Clock
Generator
Clock
Change
DIV
fSYS
INTRC-OSC
(16MHz)
WDTRC-OSC
(8kHz)
M
U
X
M
U
X
1/2048
1/256
1/16
1/2
BITCK[1:0]
BIT
M
U
X
BIT
overflow
WDT
clock
WDT
WDT
overflow
1/1
1/2
1/4
1/8
fINTRC
Figure 23. Clock Generator Block Diagram