MC68HC908GT8CFB Freescale Semiconductor, MC68HC908GT8CFB Datasheet - Page 77

• Manufacturer Part Number: MC68HC908GT8CFB
• Description: IC MCU 8K FLASH 8MHZ 44-QFP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC68HC908GT8CFB

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: SCI, SPI
• Peripherals: LVD, POR, PWM
• Number Of I /o: 34
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-QFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

Chapter 7
Internal Clock Generator (ICG) Module)
7.1 Introduction
The internal clock generator module (ICG) is used to create a stable clock source for the microcontroller
without using any external components. The ICG generates the oscillator output clock (CGMXCLK),
which is used by the low-voltage inhibit (LVI) and other modules. The ICG also generates the clock
generator output (CGMOUT), which is fed to the system integration module (SIM) to create the bus
clocks. The bus frequency will be one-fourth the frequency of CGMXCLK and one-half the frequency of
CGMOUT. Finally, the ICG generates the timebase clock (TBMCLK), which is used in the timebase
module (TBM) and the computer operating properly (COP) clock (COPCLK) which is used by the COP
module.
7.2 Features
The ICG has these features:
7.3 Functional Description
The ICG, shown in
Freescale Semiconductor
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Selectable external clock generator, either 1-pin external source or 2-pin crystal, multiplexed with
port pins
Internal clock generator with programmable frequency output in integer multiples of a nominal
frequency (307.2 kHz ± 25 percent)
Frequency adjust (trim) register to improve variability to ±4 percent
Bus clock software selectable from either internal or external clock (bus frequency range from
76.8 kHz ± 25 percent to 9.75 MHz ± 25 percent in 76.8-kHz increments
Timebase clock automatically selected from external if external clock is available
Clock monitor for both internal and external clocks
Clock enable circuit
Internal clock generator
External clock generator
Clock monitor circuit
Clock selection circuit
Do not exceed the maximum bus frequency of 8 MHz at 5.0 V and 4 MHz
at 3.0 V.
Figure
MC68HC908GT16 • MC68HC908GT8 • MC68HC08GT16 Data Sheet, Rev. 5.0
7-2, contains these major submodules:
NOTE
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