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CHAPTER 10 A/D CONVERTER
User’s Manual U15104EJ2V0UD
10.3 Registers Controlling A/D Converter
The following three registers control the A/D converter.
• A/D converter mode register 3 (ADM3)
• Analog input channel specification register 3 (ADS3)
• Power-fail comparison mode register 3 (PFM3)
(1) A/D converter mode register 3 (ADM3)
This register selects the conversion time of the analog input to be converted and starts or stops the conversion
operation.
ADM3 is set with a 1-bit or 8-bit memory manipulation instruction.
Reset input clears this register to 00H.
Figure 10-2. Format of A/D Converter Mode Register 3 (ADM3)
ADCS3
Control of A/D conversion operation
0
Stops conversion operation
1
Enables conversion operation
FR32
FR31
FR30
Selection of conversion time
0
0
0
288/f
X
(64.0
µ
s)
0
0
1
240/f
X
(53.3
µ
s)
0
1
0
192/f
X
(42.7
µ
s)
1
0
0
144/f
X
(32.0
µ
s)
1
0
1
120/f
X
(26.7
µ
s)
1
1
0
96/f
X
(21.3
µ
s)
Other than above
Setting prohibited
Cautions 1. The conversion result is undefined immediately after bit 7 (ADCS3) has been set to 1.
2. To change the data of bits 3 to 5 (FR30 to FR32), stop the A/D conversion operation.
Remarks 1. f
X
: System clock oscillation frequency
2. ( ): f
X
= 4.5 MHz
Address
FF12H
Symbol
ADM3
<7>
ADCS3
6
0
5
FR32
4
FR31
3
FR30
2
0
1
0
0
0
After reset
00H
R/W
R/W
Содержание mPD178053
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