MC68HC08AZ16 Datasheet, PDF (105/527 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Clock Generator Module (CGM)
6. Select a VCO linear range multiplier, L.
L = round
f_VCLK
f_NOM
NOTE:
where f_NOM = 4.9152MHz
7. Calculate and verify the adequacy of the VCO programmed
center-of-range frequency f_VRS.
f_VRS = (L)f_NOM
8. Verify the choice of N and L by comparing f_VCLK to f_VRS and
f_VCLKDES. For proper operation, f_VCLK must be within the
application’s tolerance of f_VCLKDES, and f_VRS must be as close
as possible to f_VCLK.
Exceeding the recommended maximum bus frequency or VCO
frequency can cause the MCU to “crash”.
9. Program the PLL registers accordingly:
a. In the upper 4 bits of the PLL programming register
(PPG), program the binary equivalent of N.
b. In the lower 4 bits of the PLL programming register
(PPG), program the binary equivalent of L.
MC68HC08AZ32
104
Clock Generator Module (CGM)
10-cgm
MOTOROLA