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16.2 Configuration of the 8/10-Bit A/D Converter
r A/D control status register (ADCS0/ADCS1)
The A/D control status register (ADCS0) sets A/D conversion mode and the A/D conversion
start/end channel.
The A/D control status register (ADCS1) sets the A/D conversion activation trigger and enable/
disable of interrupt requests and checks the interrupt request status and whether the A/D
conversion has halted/is in progress.
r A/D data register (ADCR0/ADCR1)
This register stores the results of A/D conversion. It also sets the resolution for A/D conversion,
sampling time during A/D conversion, and compare time during A/D conversion.
r Clock selector
The clock selector selects the clock for activating A/D conversion. Either 16-bit reload timer
channel 1 output or 16-bit free-running timer zero detection can be used as the activation clock.
r Decoder
This circuit sets the analog input pin to be used based on the A/D conversion end channel
setting bits (ANE0 to ANE2) and A/D conversion start channel setting bits (ANS0 to ANS2) of
the A/D control status register (ADCS0).
r Analog channel selector
This circuit selects the pin to be used from eight analog input pins.
r Sample hold circuit
This circuit maintains the input voltage from the pin set by the analog channel selector. By
maintaining the input voltage just after starting A/D conversion, it is not affected by input voltage
variations during A/D conversion (during comparison).
r D/A converter
This circuit generates a reference voltage for comparison with the input voltage maintained by
the sample hold circuit.
r Comparator
This circuit compares the input voltage maintained by the sample hold circuit with the output
voltage of the D/A converter to determine which is greater.
r Control circuit
This circuit determines the A/D conversion value based on the decision signal generated by the
comparator. When the A/D conversion has been completed, the circuit sets the conversion
result in the A/D data register (ADCR0/ADCR1) and generates an interrupt request.