MC68HC08JK1 Datasheet, PDF (91/198 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
Oscillator (OSC)
RC Oscillator (MC68HRC08xxx)
The series resistor (R_S) 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:
• C_EXT
• R_EXT
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
V_DD
R_EXT
C_EXT
See Section 18. for component value requirements.
Figure 8-2. RC Oscillator External Connections
MC68H(R)C08JL3 — Rev. 4
MOTOROLA
Oscillator (OSC)
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Technical Data
91