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CHAPTER 10 A/D CONVERTER
User’s Manual U17854EJ9V0UD
306
(2) 2.3 V
≤ AVREF ≤ 5.5 V
A/D Converter Mode Register (ADM)
Conversion Time Selection
FR2
FR1
FR0
LV1
LV0
fCLK = 2 MHz
fCLK = 5 MHz
Conversion Clock
(fAD)
0
1
480/fCLK
Setting prohibited
fCLK/12
0
1
0
1
320/fCLK
64.0
μs
fCLK/8
0
1
0
1
240/fCLK
48.0
μs
fCLK/6
0
1
0
1
160/fCLK
Setting prohibited
32.0
μs
fCLK/4
1
0
1
120/fCLK
60.0
μs
24.0
μs Note 1
fCLK/3
1
0
1
0
1
80/fCLK
40.0
μs
16.0
μs Note 2
fCLK/2
1
0
1
40/fCLK
20.0
μs Note 2
Setting prohibited
fCLK
Other than above
Setting prohibited
Notes 1. This can be set only when 2.7 V
≤ AVREF ≤ 5.5 V.
2. This can be set only when 4.0 V
≤ AVREF ≤ 5.5 V.
Cautions 1. Set the conversion times with the following conditions.
4.0 V ≤ AVREF ≤ 5.5 V: fAD = 0.6 to 3.6 MHz
2.7 V ≤ AVREF < 4.0 V: fAD = 0.6 to 1.8 MHz
2.3 V ≤ AVREF < 2.7 V: fAD = 0.6 to 1.44 MHz
2. When rewriting FR2 to FR0, LV1, and LV0 to other than the same data, stop A/D conversion
once (ADCS = 0) beforehand.
3. Change LV1 and LV0 from the default value, when 2.3 V
≤ AVREF < 2.7 V.
4. The above conversion time does not include clock frequency errors. Select conversion time,
taking clock frequency errors into consideration.
Remark
fCLK: CPU/peripheral hardware clock frequency