mc9s08jm16 Freescale Semiconductor, Inc, mc9s08jm16 Datasheet - Page 202

• Manufacturer Part Number: mc9s08jm16
• Description: S08jm 8-bit Usb Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Multi-Purpose Clock Generator (S08MCGV1)
12.5.2.4
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.
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
202
Example # 4: Moving from FEI to PEE Mode: External Crystal = 8 MHz,
Bus Frequency = 8 MHz
Figure 12-11. Flowchart of BLPI to FEE Mode Transition using a 4 MHz Crystal
MCGC2 = $36
MCGC1 = $38
OSCINIT = 1 ?
MCGC2 = $00
I
CHECK LOCK
N BLPI MODE
CHECK
OPTIONAL:
START
= 1?
YES
YES
NO
NO
MC9S08JM16 Series Data Sheet, Rev. 2
CLKST = %00?
IREFST = 0?
CHECK LOCK
IN FEE MODE
OPTIONAL:
CONTINUE
CHECK
CHECK
= 1?
YES
YES
YES
NO
NO
NO
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