mc9s08sg4 Freescale Semiconductor, Inc, mc9s08sg4 Datasheet - Page 152

• Manufacturer Part Number: mc9s08sg4
• Description: 8-bit Microcontroller Family
• Manufacturer: Freescale Semiconductor, Inc

Chapter 10 Internal Clock Source (S08ICSV2)
In FLL engaged internal mode, the ICSOUT clock is derived from the FLL clock, which is controlled by
the internal reference clock. The FLL loop will lock the frequency to 1024 times the reference frequency,
as selected by the RDIV bits. The ICSLCLK is available for BDC communications, and the internal
reference clock is enabled.
10.4.1.2
The FLL engaged external (FEE) mode is entered when all the following conditions occur:
In FLL engaged external mode, the ICSOUT clock is derived from the FLL clock which is controlled by
the external reference clock.The FLL loop will lock the frequency to 1024 times the reference frequency,
as selected by the RDIV bits. The ICSLCLK is available for BDC communications, and the external
reference clock is enabled.
10.4.1.3
The FLL bypassed internal (FBI) mode is entered when all the following conditions occur:
In FLL bypassed internal mode, the ICSOUT clock is derived from the internal reference clock. The FLL
clock is controlled by the internal reference clock, and the FLL loop will lock the FLL frequency to 1024
times the reference frequency, as selected by the RDIV bits. The ICSLCLK will be available for BDC
communications, and the internal reference clock is enabled.
10.4.1.4
The FLL bypassed internal low power (FBILP) mode is entered when all the following conditions occur:
In FLL bypassed internal low power mode, the ICSOUT clock is derived from the internal reference clock
and the FLL is disabled. The ICSLCLK will be not be available for BDC communications, and the internal
reference clock is enabled.
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CLKS bits are written to 00
IREFS bit is written to 1
RDIV bits are written to divide trimmed reference clock to be within the range of 31.25 kHz to
39.0625 kHz.
CLKS bits are written to 00
IREFS 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
CLKS bits are written to 01
IREFS bit is written to 1.
BDM mode is active or LP bit is written to 0
CLKS bits are written to 01
IREFS bit is written to 1.
BDM mode is not active and LP bit is written to 1
FLL Engaged External (FEE)
FLL Bypassed Internal (FBI)
FLL Bypassed Internal Low Power (FBILP)
MC9S08SG8 MCU Series Data Sheet, Rev. 3
Freescale Semiconductor