
11
11-2
Rev.1.0
11.1 Outline of the A-D Converters
The 32172/32173 contains two 10-bit resolution A-D converters based on successive
approximation method (A-D0 and A-D1 Converters). The A-D0 Converter has eight channels of
dedicated analog input pins (AD0IN0-AD0IN7) and eight other channels of analog input pins which
are shared with input/output ports or internal peripheral I/O input/output pins (AD0IN8-AD0IN15),
for a total of 16 channels. The A-D1 Converter has four channels of dedicated analog input pins
(AD1IN0-AD1IN3) and 12 other channels of analog input pins which are shared with input/output
ports or internal peripheral I/O input/output pins (AD1IN4-AD1IN15), for a total of 16 channels.
For both converters, the A-D converted value can be read out in either 8 bits or 10 bits.
The A-D converters have the following conversion modes and operation modes.
(1) Conversion modes
A-D conversion mode:
This is an ordinary mode, in which analog input voltages are
A-D converted.
Comparator mode (Note): In this mode, the set comparison voltage and the analog
input voltage are compared to determine which is larger or
smaller than the other (single mode only).
(2) Operation modes
Single mode: The analog input voltage on one channel is A-D converted once or
comparated (note).
Scan mode: Analog input voltages on multiple channels are sequentially A-D
converted.
(3) Types of scan modes
Single-shot scan mode: Scan operation is performed only one cycle.
Continuous scan mode: Scan operation is performed repeatedly until halted.
(4) Special operation modes
Forcibly execute single mode during scan mode operation:
Single mode conversion is forcibly executed during scan operation.
Start scan mode after executing single mode:
Scan operation is started from single mode in succession.
Restart conversion:
A-D convert operation under way is restarted in single or scan mode.
The A-D conversion and comparate speed can be selected from four speeds available: low speed
(normal or twice normal) or high speed (normal or twice normal). Also, an A-D conversion interrupt
request or DMA transfer request can be generated when the A-D conversion, comparate, or single-
shot scan is finished, or each time one cycle of continuous scan mode is finished.
Note: The comparison performed internally by the A-D converter which is of the successive approximation
type and its operation in comparator mode where the A-D converter is used as a comparator are
different. In this manual, therefore, operation in comparator mode is referred to as "comparate" in
order to discriminate it against ordinary comparison.
A-D CONVERTERS
11.1 Outline of the A-D Converters