Section 12 A/D Converter
12.1 Overview
The H8/3864 Series includes on-chip a resistance-ladder-based successive-approximation analog-to-
digital converter, and can convert up to 8 channels of analog input.
12.1.1 Features
The A/D converter has the following features.
•
10-bit resolution
•
Eight input channels
•
Conversion time: approx. 15.5 µs per channel (at 2 MHz operation)
•
Built-in sample-and-hold function
•
Interrupt requested on completion of A/D conversion
•
A/D conversion can be started by external trigger input
•
Use of module standby mode enables this module to be placed in standby mode independently
when not used.
12.1.2 Block Diagram
Figure 12-1 shows a block diagram of the A/D converter.
Figure 12-1 Block Diagram of the A/D Converter
Internal data bus
AMR
ADSR
ADRRH
ADRRL
Control logic
+
–
Com-
parator
AN
AN
AN
AN
AN
AN
AN
AN
ADTRG
AV
AV
CC
SS
Multiplexer
Reference
voltage
IRRAD
AV
CC
AV
SS
0
1
2
3
4
5
6
7
Notation:
AMR:
ADSR:
ADRR:
IRRAD:
A/D mode register
A/D start register
A/D result register
A/D conversion end interrupt request flag
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