S9S08AW16A FREESCALE [Freescale Semiconductor, Inc], S9S08AW16A Datasheet - Page 130

• Manufacturer Part Number: S9S08AW16A
• Description: HCS08 Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Internal Clock Generator (S08ICGV4)
8.1.2
This is a high-level description only. Detailed descriptions of operating modes are contained in
Section 8.4, “Functional
130
•
•
•
•
•
•
•
•
•
•
•
•
Digitally-controlled oscillator (DCO) preserves previous frequency settings, allowing fast
frequency lock when recovering from stop3 mode
DCO will maintain operating frequency during a loss or removal of reference clock
Post-FLL divider selects 1 of 8 bus rate divisors (/1 through /128)
Separate self-clocked source for real-time interrupt
Trimmable internal clock source supports SCI communications without additional external
components
Automatic FLL engagement after lock is acquired
External oscillator selectable for low power or high gain
Mode 1 — Off
The output clock, ICGOUT, is static. This mode may be entered when the STOP instruction is
executed.
Mode 2 — Self-clocked (SCM)
Default mode of operation that is entered immediately after reset. The ICG’s FLL is open loop and
the digitally controlled oscillator (DCO) is free running at a frequency set by the filter bits.
In this mode, the ICG’s FLL is used to create frequencies that are programmable multiples of the
internal reference clock.
— FLL engaged internal unlocked is a transition state that occurs while the FLL is attempting to
— FLL engaged internal locked is a state that occurs when the FLL detects that the DCO is locked
Mode 4 — FLL bypassed external (FBE)
In this mode, the ICG is configured to bypass the FLL and use an external clock as the clock source.
Mode 5 — FLL engaged external (FEE)
The ICG’s FLL is used to generate frequencies that are programmable multiples of the external
clock reference.
— FLL engaged external unlocked is a transition state that occurs while the FLL is attempting to
— FLL engaged external locked is a state which occurs when the FLL detects that the DCO is
Mode 3 — FLL engaged internal (FEI)
Modes of Operation
lock. The FLL DCO frequency is off target and the FLL is adjusting the DCO to match the
target frequency.
to a multiple of the internal reference.
lock. The FLL DCO frequency is off target and the FLL is adjusting the DCO to match the
target frequency.
locked to a multiple of the external reference.
Description.”
MC9S08AC16 Series Data Sheet, Rev. 8
Freescale Semiconductor