MC9S08RC8 Datasheet, PDF (18/234 Pages) Freescale Semiconductor, Inc – Microcontrollers

Introduction
Table 1-2. Block Versions
Module
Analog Comparator (ACMP)
Carrier Modulator Transmitter (CMT)
Keyboard Interrupt (KBI)
Serial Communications Interface (SCI)
Serial Peripheral Interface (SPI)
Timer Pulse-Width Modulator (TPM)
Central Processing Unit (CPU)
Debug Module (DBG)
FLASH
System Control
Version
1
1
1
1
3
1
2
1
1
2
1.4 System Clock Distribution
SYSTEM
RTI
RTICLKS CONTROL
OSC
LOGIC
TPM
CMT
SCI
SPI
RTI
OSCOUT*
OSC
÷2
BUSCLK
CPU
BDC
ACMP
* OSCOUT is the alternate BDC clock source for the MC9S08RC/RD/RE/RG.
RAM
FLASH
FLASH has frequency
requirements for program
and erase operation.
See Appendix A.
Figure 1-2. System Clock Distribution Diagram
Table 1-2 shows a simplified clock connection diagram for the MCU. The CPU operates at the input
frequency of the oscillator. The bus clock frequency is half of the oscillator frequency and is used by all of
the internal circuits with the exception of the CPU and RTI. The RTI can use either the oscillator input or
the internal RTI oscillator as its clock source.
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
18
Freescale Semiconductor