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FUJITSU F2MCTM-16LX User Manual

Page 359

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CHAPTER 18 8-/10-BIT A/D CONVERTER

Analog channel selector

This selector selects the pin to be used for A/D conversion from the 16-channel analog input pins by

receiving a signal from the decoder.

Sample & hold circuit

This circuit holds the input voltage selected by the analog channel selector. By holding the input voltage

immediately after A/D conversion is started, A/D conversion is performed without being affected by the

fluctuation of the input voltage during A/D conversion.

D/A converter

This converter generates the reference voltage which is compared with the input voltage held in the sample

& hold circuit.

Comparator

This comparator compares the D/A converter output voltage with input voltage held in the sample & hold

circuit to determine the amount of voltage.

Controller

This circuit determines the A/D conversion value by receiving the signal indicating the amount of voltage

determined by the comparator. When the A/D conversion results are determined, the result data is stored in

the A/D data register. If an interrupt request is enabled, an interrupt is generated.