System Clock Distribution - Freescale Semiconductor MC9S08PT60 Reference Manual

System clock distribution

1.3 System clock distribution
These series contain three on-chip clock sources:
• Internal clock source (ICS) module — The main clock source generator providing
bus clock and other reference clocks to peripherals
• External oscillator (XOSC) module — The external oscillator providing reference
clock to internal clock source (ICS), the real-time clock counter clock module (RTC)
and other MCU sub-systems.
• Low-power oscillator (LPO) module — The on-chip low-power oscillator providing
1 kHz reference clock to RTC and watchdog (WDOG).
For this device, the system clock is the bus clock.
The following figure shows a simplified clock connection diagram.
LPOCLK
1-kHz
LPO
XTAL
OSCOUT
OSC
EXTAL
ICSIRCLK
WDOG
ICSFFCLK
ICS
ICSCLK (
ICSLCLK
CLKOUT
1
N
2
BUSREF
CLKOE
System Control
The clock system supplies:
38
RTC ADC
1/2
~8 MHz after reset )
FLASH
CPU RAM
Figure 1-2. System clock distribution diagram
MC9S08PT60 Reference Manual, Rev. 4, 08/2014
NOTE
TCLK0 TCLK1
FTM0 FTM1
ACMP
MTIM0 MTIM1
BDC DBG IPC
TCLK2
FTM2 CRC TSI
SCI0
SPI0
SCI1
IIC
SPI1
SCI2
Freescale Semiconductor, Inc.
KBI0
KBI1