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CHAPTER 13 OPERATIONAL AMPLIFIER
User’s Manual U19780EJ2V0UD
356
13.3 Registers Used in Operational Amplifier
The operational amplifier uses the following three registers.
•
Operational
amplifier
control register (OAC)
•
A/D port configuration register (ADPC)
•
Port mode registers 2 and 8 (PM2, PM8)
(1) Operational
amplifier
control register (OAC)
AMP0 to AMP2 control the operations of operational amplifier.
OAC can be set by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation clears AMP0M to 00H.
Figure 13-2. Format of Operational Amplifier Control Register (OAC)
Address: FF3BH After reset: 00H R/W
Symbol
7 6 5 4 3 2 1 0
OAC
OAIM1
OAIM0
0 0 0
OAEN2
OAEN1
OAEN0
OAIM1
OAIM0
Operational amplifier operation mope
0
0
Mode 2 (Slew rate : 0.4 V/
μ
s (TYP.))
0
1
Mode 3 (Slew rate : 1.4 V/
μ
s (TYP.))
1
0
Setting
prohibited
1
1
Mode 1 (Slew rate : 0.2 V/
μ
s (TYP.))
OAEN2
Operational amplifier 2 operation control
0
Stops operational amplifier 2 operation
1
Enables operational amplifier 2 operation
OAEN1
Operational amplifier 1 operation control
0
Stops operational amplifier 1 operation
1
Enables operational amplifier 1 operation
OAEN0
Operational amplifier 0 operation control
0
Stops operational amplifier 0 operation
1
Enables operational amplifier 0 operation
Cautions 1. Use the ADPC registers to select a pin used in the operational amplifier as an analog input.
2. When using as digital inputs the pins of port 2, 8, which are not used with the operational
amplifier, when the operational amplifier is used, make sure that the input levels of digital
input ports are fixed.