CHAPTER 12 A/D CONVERTER
User’s Manual U15109EJ3V0UD
459
(2/2)
Selection of conversion time
f
XX
ADPS
FR2
FR1
FR0
Conversion time
Note 1
+ stabilization time
Note 2
20 MHz
18.87 MHz
16 MHz
0
0
0
0
168/f
XX
8.4
µ
s
8.9
µ
s
Setting prohibited
0
0
0
1
120/f
XX
6.0
µ
s
6.4
µ
s
7.5
µ
s
0
0
1
0
84/f
XX
Setting prohibited Setting prohibited 5.25
µ
s
0
0
1
1
60/f
XX
Setting prohibited Setting prohibited Setting prohibited
0
1
0
0
48/f
XX
Setting prohibited Setting prohibited Setting prohibited
0
1
0
1
36/f
XX
Setting prohibited Setting prohibited Setting prohibited
0
1
1
0
Setting prohibited
Setting prohibited Setting prohibited Setting prohibited
0
1
1
1
12/f
XX
Setting prohibited Setting prohibited Setting prohibited
1
0
0
0
168/f
XX
+ 64/f
XX
8.4 + 3.2
µ
s
8.9 + 3.4
µ
s
Setting prohibited
1
0
0
1
120/f
XX
+ 60/f
XX
6.0 + 3.0
µ
s
6.4 + 3.2
µ
s
7.5 + 3.75
µ
s
1
0
1
0
84/f
XX
+ 42/f
XX
Setting prohibited Setting prohibited 5.25 + 2.63
µ
s
1
0
1
1
60/f
XX
+ 30/f
XX
Setting prohibited Setting prohibited Setting prohibited
1
1
0
0
48/f
XX
+ 24/f
XX
Setting prohibited Setting prohibited Setting prohibited
1
1
0
1
36/f
XX
+ 18/f
XX
Setting prohibited Setting prohibited Setting prohibited
1
1
1
0
Setting prohibited
Setting prohibited Setting prohibited Setting prohibited
1
1
1
1
12/f
XX
+ 6/f
XX
Setting prohibited Setting prohibited Setting prohibited
EGA1
EGA0
Valid edge specification for external trigger signal
0
0
No edge detection
0
1
Detected at falling edge
1
0
Detected at rising edge
1
1
Detected at both rising and falling edges
ADPS
Comparator control while A/D conversion is stopped (ADCS = 0)
0
Comparator ON
1
Comparator OFF
Notes 1.
Conversion time (actual A/D conversion time).
Always set the time to 5
µ
s
≤
Conversion time
≤
10
µ
s.
2.
Stabilization time (setup time of A/D converter)
Each A/D conversion requires “conversion time + stabilization time”. There is no stabilization time
when ADPS = 0.
Cautions 1.
The A/D converter cannot be used when the operation frequency is 2.4 to 3.6 MHz.
2.
Cut the current consumption by setting the ADPS bit to 1 when the ADCS bit is set to 0.