MC9S08AC16_09 Datasheet, PDF (127/330 Pages) Freescale Semiconductor, Inc – HCS08 Microcontrollers

Chapter 8
Internal Clock Generator (S08ICGV4)
The internal clock generation (ICG) module is used to generate the system clocks for the MC9S08AC16
Series MCU. The analog supply lines V_DDA and V_SSA are internally derived from the MCU’s V_DD and
V_SS pins. Electrical parametric data for the ICG may be found in Appendix A, “Electrical Characteristics
and Timing Specifications.”
ICGERCLK
FFE
SYSTEM
CONTROL
LOGIC
TPMCLK
RTI
TPM1
TPM2
IIC1
SCI1
SCI2
SPI1
÷2
ICG
XCLK*
COP 1 kHz
ICGOUT
÷2
ICGLCLK*
BUSCLK
CPU
BDC
TPM3
ADC1
RAM
FLASH
* ICGLCLK is the alternate BDC clock source for the MC9S08AC16 Series.
* XCLK is the fixed-frequency clock.
ADC has min and max
frequency requirements.
See the Electricals appendix
and the ADC chapter.
FLASH has frequency
requirements for program
and erase operation.
See the Electricals
appendix.
Figure 8-1. System Clock Distribution Diagram
NOTE
Freescale Semiconductor recommends that FLASH location 0xFFBE be
reserved to store a nonvolatile version of ICGTRM. This will allow
debugger and programmer vendors to perform a manual trim operation and
store the resultant ICGTRM value for users to access at a later time.
MC9S08AC16 Series Data Sheet, Rev. 8
Freescale Semiconductor
127