
CHAPTER 13 A/D CONVERTER
User’s Manual U16541EJ4V0UD
454
Table 13-2. Conversion Time Selection in Normal Conversion Mode (ADA0HS1 Bit = 0)
A/D Conversion Time
ADA0FR2
to
ADA0FR0
Bits
Stabilization Time
+ Conversion Time + Wait Time
fXX = 20 MHz
fXX = 16 MHz
fXX = 4 MHz
Trigger Response
Time
000
13/fXX + 26/fXX + 26/fXX
Setting prohibited
16.25
s
4/fXX
001
26/fXX + 52/fXX + 52/fXX
6.5
s
8.125
s
Setting prohibited
5/fXX
010
39/fXX + 78/fXX + 78/fXX
9.75
s
12.1875
s
Setting prohibited
6/fXX
011
50/fXX + 104/fXX + 104/fXX
12.9
s
16.125
s
Setting prohibited
7/fXX
100
50/fXX + 130/fXX + 130/fXX
15.5
s
19.375
s
Setting prohibited
8/fXX
101
50/fXX + 156/fXX + 156/fXX
18.1
s
22.625
s
Setting prohibited
9/fXX
110
50/fXX + 182/fXX + 182/fXX
20.7
s
Setting prohibited
10/fXX
111
50/fXX + 208/fXX + 208/fXX
23.3
s
Setting prohibited
11/fXX
Remark
Stabilization time:
A/D converter setup time (1
s or longer)
Conversion time:
Actual A/D conversion time (2.6 to 10.4
s)
Wait time:
Wait time inserted before the next conversion
Trigger response time: If a software trigger, external trigger, or timer trigger is generated after the
stabilization time, it is inserted before the conversion time.
In the normal conversion mode, the conversion is started after the stabilization time elapsed from the
ADA0M0.ADA0CE bit is set to 1, and A/D conversion is performed only during the conversion time (2.6 to
10.4
s). Operation is stopped after the conversion ends and the A/D conversion end interrupt request
signal (INTAD) is generated after the wait time is elapsed.
Because the conversion operation is stopped during the wait time, operation current can be reduced.
Cautions 1. Set as 2.6
s ≤ conversion time ≤ 10.4 s.
2. During A/D conversion, if the ADA0M0, ADA0M2, ADA0S, ADA0PFM, and ADA0PFT
registers are written or trigger is input, reconversion is carried out. However, if the
stabilization time end timing conflicts with the writing to these registers, or if the
stabilization time end timing conflicts with the trigger input, the stabilization time of 64
clocks is reinserted.
If it conflicts again with the reinserted stabilization time end timing, the stabilization
time is reinserted. Therefore do not set the trigger input interval and control register
write interval to 64 clocks or below.