MB91133/MB91F133
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11. 8-/10-bit A/D Converter
The 8-/10-bit A/D converter features functions that convert analog input voltages to 10- or 8-bit digital values
using the RC sequential comparison conversion method. The input signal is selected from 8-channel analog
input pins and three types of conversion initiation can be selected from software, internal clock, or external pin
trigger.
characteristics of 8-/10-bit A/D converter
The A/D conversion function for converting analog voltages (input voltages) input into the analog input pins to
digital values has the following characteristics.
Conversion time is minimum 5.0
μ
s (including sampling time when machine clock is 33 MHz) .
Conversion method is RC sequential comparison conversion method with sample holding circuit.
10- or 8-bit resolution can be selected.
Analog input pin can be selected from 8 channels using the program.
interruption request can be generated when A/D conversion ends.
Data is not lost even during continuous conversion as conversion data protection function works while inter-
ruptions are permitted.
Initiation factors for conversion can be selected from software, 16-bit reload timer 2 (rising edge) , or external
pin trigger (L level detection) .
There are three types of conversion modes.
Table 13.1-1 Conversion Modes of 8-/10-bit A/D Converter
Single Conversion Operation
Conversion Modes
Scan Conversion Operation
Single conversion mode
Converts the specified channel (1 channel
only) once and ends.
Converts a series of channels (up to 8
channels can be specified) once and ends.
Consecutive
conversion mode
Repeatedly converts the specified channel
(1 channel only) .
Repeatedly converts a series of channels
(up to 8 channels can be specified) .
Stop conversion mode
Suspends after converting the specified
channel (1 channel only) once and waits
until the next one is initiated.
Converts a series of channels (up to 8
channels can be specified) but is suspend-
ed between each channel conversion and
waits until the next one is initiated.