MC9S08DZ60 Datasheet, PDF (144/396 Pages) Freescale Semiconductor, Inc – Microcontrollers

Multi-Purpose Clock Generator (S08MCGV1)
• LP bit is written to 0
In FLL bypassed internal mode, the MCGOUT clock is derived from the internal reference clock. The FLL
clock is controlled by the internal reference clock, and the FLL clock frequency locks to 1024 times the
reference frequency, as selected by the RDIV bits. The MCGLCLK is derived from the FLL and the PLL
is disabled in a low power state.
8.4.1.4 FLL Bypassed External (FBE)
In FLL bypassed external (FBE) mode the MCGOUT clock is derived from the external reference clock
and the FLL is operational but it’s output clock is not used. This mode is useful to allow the FLL to acquire
it’s target frequency while the MCGOUT clock is driven from the external reference clock.
The FLL bypassed external mode is entered when all the following conditions occur:
• CLKS bits are written to 10
• IREFS bit is written to 0
• PLLS bit is written to 0
• RDIV bits are written to divide reference clock to be within the range of 31.25 kHz to 39.0625 kHz
• LP bit is written to 0
In FLL bypassed external mode, the MCGOUT clock is derived from the external reference clock. The
external reference clock which is enabled can be an external crystal/resonator or it can be another external
clock source.The FLL clock is controlled by the external reference clock, and the FLL clock frequency
locks to 1024 times the reference frequency, as selected by the RDIV bits. The MCGLCLK is derived from
the FLL and the PLL is disabled in a low power state.
8.4.1.5 PLL Engaged External (PEE)
The PLL engaged external (PEE) mode is entered when all the following conditions occur:
• CLKS bits are written to 00
• IREFS bit is written to 0
• PLLS bit is written to 1
• RDIV bits are written to divide reference clock to be within the range of 1 MHz to 2 MHz
In PLL engaged external mode, the MCGOUT clock is derived from the PLL clock which is controlled by
the external reference clock. The external reference clock which is enabled can be an external
crystal/resonator or it can be another external clock source The PLL clock frequency locks to a
multiplication factor, as selected by the VDIV bits, times the reference frequency, as selected by the RDIV
bits. If BDM is enabled then the MCGLCLK is derived from the DCO (open-loop mode) divided by two.
If BDM is not enabled then the FLL is disabled in a low power state.
MC9S08DZ60 Series Data Sheet, Rev. 1 Draft E
144
PRELIMINARY
Freescale Semiconductor
Subject to Change