MC9S08GB60A Datasheet, PDF (103/302 Pages) Freescale Semiconductor, Inc – HCS08 Microcontrollers

Chapter 7
Internal Clock Generator (S08ICGV2)
The MC9S08GBxxA/GTxxA microcontroller provides one internal clock generation (ICG) module to
create the system bus frequency. All functions described in this section are available on the
MC9S08GBxxA/GTxxA microcontroller. The EXTAL and XTAL pins share port G bits 2 and 1,
respectively. 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.”
SYSTEM
CONTROL
LOGIC
ICGERCLK
RTI
FFE
TPM1
TPM2
IIC1
SCI1
SCI2
SPI1
÷2
ICG
FIXED FREQ CLOCK (XCLK)
ICGOUT
÷2
ICGLCLK*
BUSCLK
CPU
BDC
ATD1
RAM
FLASH
ATD has min and max
Flash has frequency
frequency requirements. See
requirements for program
* ICGLCLK is the alternate BDC clock source for the MC9S08GBxxA/GTxxA. Chapter 1, “Device Overview” and
and erase operation.
Appendix A, “Electrical Characteristics. See Appendix A, “Electrical
Characteristics.
Figure 7-1. System Clock Distribution Diagram
NOTE
Freescale Semiconductor recommends that flash location $FFBE 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.
MC9S08GB60A Data Sheet, Rev. 2
Freescale Semiconductor
103