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MC68HC08JL3_05 Datasheet, PDF (91/198 Pages) Freescale Semiconductor, Inc – Microcontrollers
The series resistor (RS) is included in the diagram to follow strict Pierce
oscillator guidelines and may not be required for all ranges of operation,
especially with high frequency crystals. Refer to the crystal
manufacturer’s data for more information.
8.4 RC Oscillator (MC68HRC08xxx)
The RC oscillator circuit is designed for use with external R and C to
provide a clock source with tolerance less than 10%.
In its typical configuration, the RC oscillator requires two external
components, one R and one C. Component values should have a
tolerance of 1% or less, to obtain a clock source with less than 10%
tolerance. The oscillator configuration uses two components:
• CEXT
• REXT
From SIM
To SIM
2OSCOUT
To SIM
OSCOUT
SIMOSCEN EN
Ext-RC
Oscillator
RCCLK
÷2
MCU
OSC1
0
1
PTA6
I/O
PTA6/RCCLK (OSC2)
PTA6
PTA6EN
VDD
REXT
CEXT
See Section 18. for component value requirements.
Figure 8-2. RC Oscillator External Connections
MC68H(R)C08JL3 — Rev. 4.1
Freescale Semiconductor
Technical Data
91