MC9S08FL16 Datasheet, PDF (4/34 Pages) Freescale Semiconductor, Inc – 8-Bit S08 Central Processor Unit (CPU)

System Clock Distribution
2 System Clock Distribution
MC9S08FL16 series use ICS module as clock sources. The ICS module can use internal or external clock
source as reference to provide up to 20 MHz CPU clock. The output of ICS module includes,
• OSCOUT — XOSC output provides external reference clock to ADC.
• ICSFFCLK — ICS fixed frequency clock reference (around 32.768 kHz) provides double of the
fixed lock signal to TPMs and MTIM16.
• ICSOUT — ICS CPU clock provides double of the bus clock which is basic clock reference of
peripherals.
• ICSLCLK — Alternate BDC clock provides debug signal to BDC module.
The TCLK pin is an extra external clock source. When TCLK is enabled, it can provide alternate clock
source to TPMs and MTIM16. The on-chip 1 kHz clock provides clock source of COP module.
1 kHz
TCLK
COP
TPM1
TPM2
MTIM16
ADC
OSCOUT
ICSFFCLK _÷2 FIXED CLOCK (XCLK)
ICS
ICSOUT
BUS CLOCK
÷2
ICSLCLK
XOSC
EXTAL XTAL
CPU
SCI
BDC
FLASH
RAM
IPC
Figure 2. System Clock Distribution Diagram
MC9S08FL16 Series Data Sheet, Rev. 2
4
Freescale Semiconductor