MC68HC908LB8_05 Datasheet, PDF (24/234 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

General Description
1.7 System Clock Distribution
V_DD
XRC
R_EXT
IRC
OSC
SIM
MUX
BUSCLKX4
BUSCLKX4
÷2 ^BUSCLKX2
BUSCLK
÷4
PWM HRP COP TIM ADC KBI
CPU FLASH RAM
MON ROM
FLASH
PROGRAMMING
ROM
Figure 1-3. System Clock Distribution Diagram
Some of the modules inside the MCU use different clock sources. Figure 1-3 shows a simplified clock
connection diagram. The OSC supplies the clock sources:
• BUSCLKX4 is the basic reference clock of the device. It is either:
– The external crystal oscillator
– An external clock source
– An external RC oscillator
– The internal oscillator
MC68HC908LB8 Data Sheet, Rev. 1
24
Freescale Semiconductor