MC68HC05JJ6 Datasheet, PDF (27/216 Pages) Freescale Semiconductor, Inc – General Release Specification Microcontrollers

General Description
1.7.2 Ceramic Resonator Oscillator
In cost-sensitive applications, a ceramic resonator can be used in place
of the crystal. The circuit in Figure 1-3 (a) can be used for a ceramic
resonator. The resonator manufacturer’s recommendations should be
followed, as the resonator parameters determine the external
component values required for maximum stability and reliable starting.
The load capacitance values used in the oscillator circuit design should
include all stray capacitances. The ceramic resonator and components
should be mounted as close as possible to the pins for startup
stabilization and to minimize output distortion. An internal startup resistor
of approximately 2 MΩ can be provided by the shunt resistor mask
option between OSC1 and OSC2 for the ceramic resonator type
oscillator. The ceramic resonator configuration is enabled by choosing
the crystal selection in the connections oscillator mask option.
1.7.3 RC Oscillator
The lowest cost oscillator is the RC oscillator configuration where a
resistor is connected between the two oscillator pins as shown in Figure
1-3 (b). The internal startup resistor of approximately 2 MΩ is not
recommended between OSC1 and OSC2 for the RC-type oscillator.
The RC oscillator configuration is selected by the oscillator connections
mask option.
1.7.4 External Clock
An external clock from another CMOS-compatible device can be
connected to the OSC1 input, with the OSC2 input not connected, as
shown in Figure 1-3 (c). This configuration is possible regardless of
whether the crystal/ceramic resonator or RC oscillator configuration is
used.
MC68HC05JJ6/MC68HC05JP6 — Rev. 3.2
Freescale Semiconductor
General Description
General Release Specification
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