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CHAPTER 12 A/D CONVERTER
User’s Manual U19780EJ2V0UD
329
Table 12-2. A/D Conversion Time Selection
(1) Normal mode 1 : 2.7 V
≤
AV
DD
≤
5.5 V (Stops operation
of A/D converter booster circuit)
Note 1
A/D Converter Mode Register (ADM)
Conversion Time Selection
FR2 FR1 FR0 LV1 LV0
f
CPU
= 1 MHz
f
CPU
= 8 MHz
f
CPU
= 10 MHz f
CPU
= 20 MHz
Conversion
Clock
(f
AD
)
0 0 0
240/f
CPU
30
μ
s 24
μ
s 12
μ
s f
CPU
/12
0 0 1
160/f
CPU
20
μ
s 16
μ
s 8
μ
s f
CPU
/8
0 1 0
120/f
CPU
15
μ
s 12
μ
s 6
μ
s f
CPU
/6
0 1 1
100/f
CPU
12.5
μ
s 10
μ
s 5
μ
s f
CPU
/5
1 0 0
80/f
CPU
10
μ
s 8
μ
s f
CPU
/4
1 0 1
60/f
CPU
Setting
prohibited
7.5
μ
s 6
μ
s f
CPU
/3
1 1 0
40/f
CPU
40
μ
s 5
μ
s f
CPU
/2
1 1 1
0 0
20/f
CPU
20
μ
s
Setting
prohibited
Setting
prohibited
Setting
prohibited
f
CPU
(2) Normal mode 2 : 2.3 V
≤
AV
DD
≤
5.5 V (Operation
of A/D converter booster circuit)
Notes 1, 2
A/D Converter Mode Register (ADM)
Conversion Time Selection
FR2 FR1 FR0 LV1 LV0
f
CPU
= 1 MHz
f
CPU
= 8 MHz
f
CPU
= 10 MHz f
CPU
= 20 MHz
Conversion
Clock
(f
AD
)
0 0 0
240/f
CPU
30
μ
s 24
μ
s 12
μ
s f
CPU
/12
0 0 1
160/f
CPU
20
μ
s 16
μ
s 8
μ
s f
CPU
/8
0 1 0
120/f
CPU
15
μ
s 12
μ
s 6
μ
s f
CPU
/6
0 1 1
100/f
CPU
12.5
μ
s 10
μ
s 5
μ
s f
CPU
/5
1 0 0
80/f
CPU
10
μ
s 8
μ
s f
CPU
/4
1 0 1
60/f
CPU
Setting
prohibited
7.5
μ
s 6
μ
s f
CPU
/3
1 1 0
40/f
CPU
40
μ
s 5
μ
s f
CPU
/2
1 1 1
0 1
20/f
CPU
20
μ
s
Setting
prohibited
Setting
prohibited
Setting
prohibited
f
CPU
(3) Low-voltage mode : 1.8 V
≤
AV
DD
≤
5.5 V (Operation
of A/D converter booster circuit)
Notes 1, 2
A/D Converter Mode Register (ADM)
Conversion Time Selection
FR2 FR1 FR0 LV1 LV0
f
CPU
= 1 MHz
f
CPU
= 8 MHz
f
CPU
= 10 MHz f
CPU
= 20 MHz
Conversion
Clock
(f
AD
)
0 0 0
276/f
CPU
34.5
μ
s 27.6
μ
s 13.8
μ
s f
CPU
/12
0 0 1
184/f
CPU
23
μ
s 18.4
μ
s 9.2
μ
s f
CPU
/8
0 1 0
138/f
CPU
17.3
μ
s 13.8
μ
s 6.9
μ
s f
CPU
/6
0 1 1
115/f
CPU
14.4
μ
s 11.5
μ
s f
CPU
/5
1 0 0
92/f
CPU
11.5
μ
s 9.2
μ
s f
CPU
/4
1 0 1
69/f
CPU
Setting
prohibited
8.96
μ
s 6.9
μ
s f
CPU
/3
1 1 0
46/f
CPU
46
μ
s f
CPU
/2
1 1 1
1 0
23/f
CPU
23
μ
s
Setting
prohibited
Setting
prohibited
Setting
prohibited
f
CPU
(
Note
,
Caution
, and
Remark
are listed on next page.)