MC9S08JM16CGTE FREESCALE [Freescale Semiconductor, Inc], MC9S08JM16CGTE Datasheet - Page 204

• Manufacturer Part Number: MC9S08JM16CGTE
• Description: Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Multi-Purpose Clock Generator (S08MCGV1)
204
3. Then, BLPE mode transitions into PBE mode:
4. Last, PBE mode transitions into PEE mode:
c) MCGC1 = 0x98 (%10011000)
d) MCGC3 = 0x44 (%01000100)
e) Loop until PLLST (bit 5) in MCGSC is set, indicating that the current source for the PLLS
a) Clear LP (bit 3) in MCGC2 to 0 here to switch to PBE mode
b) Then loop until LOCK (bit 6) in MCGSC is set, indicating that the PLL has acquired lock
a) MCGC1 = 0x18 (%00011000)
b) Now, With an RDIV of divide-by-8, a BDIV of divide-by-1, and a VDIV of multiply-by-16,
– RDIV (bits 5-3) set to %011, or divide-by-8 because 8 MHz / 8= 1 MHz which is in the 1
– PLLS (bit 6) set to 1, selects the PLL. In BLPE mode, changing this bit only prepares the
– VDIV (bits 3-0) set to %0100, or multiply-by-16 because 1 MHz reference * 16 = 16 MHz.
clock is the PLL
– CLKS (bits7 and 6) in MCGSC1 set to %00 in order to select the output of the PLL as the
– Loop until CLKST (bits 3 and 2) in MCGSC are %11, indicating that the PLL output is
MCGOUT = [(8 MHz / 8) × 16] / 1 = 16 MHz, and the bus frequency is MCGOUT / 2, or 8
MHz
MHz to 2 MHz range required by the PLL. In BLPE mode, the configuration of the RDIV
does not matter because both the FLL and PLL are disabled. Changing them only sets up the
the dividers for PLL usage in PBE mode
MCG for PLL usage in PBE mode
In BLPE mode, the configuration of the VDIV bits does not matter because the PLL is
disabled. Changing them only sets up the multiply value for PLL usage in PBE mode
system clock source
selected to feed MCGOUT in the current clock mode
MC9S08JM16 Series Data Sheet, Rev. 2
Freescale Semiconductor