MC1321x Introduction
MC1321x Reference Manual, Rev. 1.6
Freescale Semiconductor
1-15
•
Internal Clock Generator (ICG) - Supports external clock source or external crystal oscillator and
has internal reference generator with two controlled sources. One is approximately 8 MHz and can
be selected as local clock for background debug controller. The other is typically 243 kHz and can
be trimmed for a low-cost MCU clock source
•
Inter-integrated circuit (IIC) with 100 kbps operation
•
In-circuit debug and flash programming available via on-chip background debug module (BDM)
•
Up to 32 MCU GPIO with programmable pullups - The HCS08 MCU has a total of 7 ports with
each having 8 GPIO. Because of the MC1321x package limitations, only 32 of the GPIO are
available for use. There are multiple use IO, high drive IO, programmable pullups and other
features. The MCU GPIO are covered in detail in
Chapter 13, “MCU Parallel Input/Output”
.
Unused GPIO and GPIO not pinned-out should be initialized to a known condition.
1.8.4
MCU Internal Clock Distribution
Some of the modules inside the MCU have clock source choices.
shows a simplified clock
connection diagram.
Figure 1-9. MCU Internal Clock Distribution
The clocks are derived from the ICG and the ICG supplies the clock sources:
•
ICGOUT is an output of the ICG module. It is one of the following:
— The external crystal oscillator
— An external clock source (can be driven by CLKO output from the modem)
— The output of the digitally-controlled oscillator (DCO) in the frequency-locked loop
sub-module
Control bits inside the ICG determine which source is connected
•
FFE is a control signal generated inside the ICG. If the frequency of ICGOUT > 4
×
the frequency
of ICGERCLK, this signal is a logic 1 and the fixed-frequency clock will be the ICGERCLK.
Otherwise the fixed-frequency clock will be BUSCLK
TPM1
TPM2
IIC1
SCI1
SCI2
SPI1
BDC
CPU
ATD1
RAM
FLASH
ICG
ICGOUT
÷
2
FFE
SYSTEM
LOGIC
BUSCLK
ICGLCLK*
CONTROL
FIXED FREQ CLOCK (XCLK)
ICGERCLK
RTI
ATD has min and max
frequency requirements.
See
FLASH has frequency
requirements for
program and erase
* ICGLCLK is the alternate BDC
clock source for the HCS08.
÷
2
Содержание freescale semiconductor MC13211
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Страница 166: ...Modem Modes of Operation MC1321x Reference Manual Rev 1 6 7 22 Freescale Semiconductor...
Страница 172: ...Modem Interrupt Description MC1321x Reference Manual Rev 1 6 8 6 Freescale Semiconductor...
Страница 186: ...MCU Modes of Operation MC1321x Reference Manual Rev 1 6 10 8 Freescale Semiconductor...
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Страница 244: ...MCU Parallel Input Output MC1321x Reference Manual Rev 1 6 13 20 Freescale Semiconductor...
Страница 288: ...MCU Central Processor Unit CPU MC1321x Reference Manual Rev 1 6 15 20 Freescale Semiconductor...
Страница 308: ...MCU Timer PWM TPM Module MC1321x Reference Manual Rev 1 6 17 16 Freescale Semiconductor...
Страница 338: ...Inter Integrated Circuit IIC MC1321x Reference Manual Rev 1 6 19 14 Freescale Semiconductor...
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