mc9s08gt16a Freescale Semiconductor, Inc, mc9s08gt16a Datasheet - Page 129

• Manufacturer Part Number: mc9s08gt16a
• Description: Hcs08 Microcontrollers 8-bit Microcontroller Family
• Manufacturer: Freescale Semiconductor, Inc

9.1.3
Figure 9-3
(ICG) module. This section includes a general description and a feature list.
9.2
The oscillator pins are used to provide an external clock source for the MCU. The oscillator pins are gain
controlled in low-power mode (default). Oscillator amplitudes in low-power mode are limited to
approximately 1 V, peak-to-peak.
9.2.1
If upon the first write to ICGC1, either the FEE mode or FBE mode is selected, this pin functions as either
the external clock input or the input of the oscillator circuit as determined by REFS. If upon the first write
to ICGC1, either the FEI mode or SCM mode is selected, this pin is not used by the ICG.
9.2.2
If upon the first write to ICGC1, either the FEE mode or FBE mode is selected, this pin functions as the
output of the oscillator circuit. If upon the first write to ICGC1, either the FEI mode or SCM mode is
Freescale Semiconductor
External Signal Description
(SEE NOTE 2)
(SEE NOTE 2)
is a top-level diagram that shows the functional organization of the internal clock generation
Block Diagram
EXTAL — External Reference Clock / Oscillator Input
XTAL — Oscillator Output
V
V
DDA
SSA
EXTAL
XTAL
NOTES:
1. See chip level clock routing diagram for specific use of ICGOUT, FFE, ICGLCLK, ICGERCLK
2. Not all HCS08 microcontrollers have unique supply pins for the ICG. See the device pin assignments.
INTERNAL
REFERENCE
GENERATORS
WITH EXTERNAL REF
OSCILLATOR (OSC)
SELECT
TYP 243 kHz
MC9S08GT16A/GT8A Data Sheet, Rev. 1
IRG
8 MHz
RG
Figure 9-3. ICG Block Diagram
SELECT
REF
ICGERCLK
ICGIRCLK
LOCAL CLOCK FOR OPTIONAL USE WITH BDC
AND CLOCK DETECTOR
FREQUENCY
LOOP (FLL)
LOCKED
LOSS OF LOCK
ICG
DCO
ICGDCLK
OUTPUT
SELECT
CLOCK
SELECT
CLOCK
SELECT
CLOCK
FIXED
Internal Clock Generator (S08ICGV4)
ICGLCLK
FFE
/R
ICGOUT
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