235
CHAPTER 13 A/D CONVERTER
User’s Manual U12697EJ3V0UM
Cautions 1. Set the A/D conversion time as follows:
When V
DD
= 2.7 V to 5.5 V: 14
µ
s or more
When V
DD
= 2.0 V to 2.7 V: 24
µ
s or more
When V
DD
= 1.9 V to 2.0 V: 48
µ
s or more (
µ
PD78F4225 only)
When V
DD
= 1.8 V to 2.0 V: 48
µ
s or more (
µ
PD784224, 784225 only)
2. When overwriting FR0 to FR2 to different data, temporarily halt the A/D conversion
operations before continuing.
3. If ADCS is set after ADCE is set and the following time has elapsed, the first A/D
conversion value can be used.
When V
DD
= 2.7 V to 5.5 V: 14
µ
s or more
When V
DD
= 2.0 V to 2.7 V: 24
µ
s or more
When V
DD
= 1.9 V to 2.0 V: 48
µ
s or more (
µ
PD78F4225 only)
When V
DD
= 1.8 V to 2.0 V: 48
µ
s or more (
µ
PD784224, 784225 only)
4. If ADCS is set when ADCE = 0, the first A/D conversion value is undefined.
Remark
f
XX
: Main system clock frequency (f
X
or f
X
/2)
f
X
:
Main system clock oscillation frequency
(2) A/D converter input selection register (ADIS)
Used to specify the input ports for analog signals to be A/D converted.
ADIS can be set by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets ADIS to 00H.
Figure 13-3. Format of A/D Converter Input Selection Register (ADIS)
Address: 0FF81H After reset: 00H R/W
Symbol
7
6
5
4
3
2
1
0
ADIS
0
0
0
0
0
ADIS2
ADIS1
ADIS0
ADIS2
ADIS1
ADIS0
Analog input channel setting
0
0
0
ANI0
0
0
1
ANI1
0
1
0
ANI2
0
1
1
ANI3
1
0
0
ANI4
1
0
1
ANI5
1
1
0
ANI6
1
1
1
ANI7
