Freescale Semiconductor DEMO9S08DZ60 Demo Board DEMO9S08DZ60 DEMO9S08DZ60 数据表
产品代码
DEMO9S08DZ60
Chapter 8 Multi-Purpose Clock Generator (S08MCGV1)
MC9S08DZ60 Series Data Sheet, Rev. 4
160
Freescale Semiconductor
Figure 8-11. Flowchart of BLPI to FEE Mode Transition using a 4 MHz crystal
8.5.2.4
Example # 4: Moving from FEI to PEE Mode: External Crystal = 8 MHz,
Bus Frequency = 8 MHz
Bus Frequency = 8 MHz
In this example, the MCG will move through the proper operational modes from FEI to PEE mode until
the 8 MHz crystal reference frequency is set to achieve a bus frequency of 8 MHz.
the 8 MHz crystal reference frequency is set to achieve a bus frequency of 8 MHz.
This example is similar to example number one except that in this case the frequency of the external crystal
is 8 MHz instead of 4 MHz. Special consideration must be taken with this case since there is a period of
time along the way from FEI mode to PEE mode where the FLL operates based on a reference clock with
a frequency that is greater than the maximum allowed for the FLL. This occurs because with an 8 MHz
is 8 MHz instead of 4 MHz. Special consideration must be taken with this case since there is a period of
time along the way from FEI mode to PEE mode where the FLL operates based on a reference clock with
a frequency that is greater than the maximum allowed for the FLL. This occurs because with an 8 MHz
MCGC2 = $36
CHECK
OSCINIT = 1 ?
MCGC1 = $38
CHECK
IREFST = 0?
CHECK
CLKST = %00?
CONTINUE
IN FEE MODE
START
I
N BLPI MODE
YES
YES
NO
NO
NO
MCGC2 = $00
OPTIONAL:
CHECK LOCK
= 1?
YES
NO
YES
OPTIONAL:
CHECK LOCK
= 1?
YES
NO