Freescale Semiconductor, Inc.
GENERAL RELEASE SPECIFICATION
When the internal RC oscillator is being used, these limitations apply:
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1. Since the internal RC oscillator is running asynchronously with respect to the
PH2 clock, the conversion complete bit (CC) in the A/D status and control
register must be used to determine when a conversion sequence has been
completed.
2. Electrical noise will slightly degrade the accuracy of the A/D converter. The
A/D converter is synchronized to read voltages during the quiet period of the
clock driving it. Since the internal and external clocks are not synchronized
the A/D converter occasionally will measure an input when the external clock
is making a transition.
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3. If the PH2 clock is 1 MHz or greater (for instance, external oscillator 2 MHz
or greater), the internal RC oscillator should be turned off and the external
oscillator used as the conversion clock.
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9.3.3 Multi-Channel Operation
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An input multiplexer allows the A/D converter to select from one of four external
analog signals. Port C pins PC3 through PC6 are shared with the inputs to the
multiplexer.
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A
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ANALOG-TO-DIGITAL CONVERTER
Rev. 1.0
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