HT45R38
EXIT_INT_ISR:
mov
mov
mov
reti
a,status_stack
STATUS,a
a,acc_stack
; restore STATUS from user defined memory
; restore ACC from user defined memory
OP Amplifier
The device contains an internal Operational Amplifier, which can be used for amplification purposes. The OPA can be
disabled or enabled under software control and by the OPA configuration option.
OPA
Configuration
Option
OPAEN
Register
PCR2~PCR0
Register
Function
000B
PE0/AN0/OPO is digital input pin, OPA is disabled.
001B
010B
011B
100B
101B
0
PE0/AN0/OPO is ADC channel 0 input pin, OPA is disabled.
PE0/AN0/OPO is OPA output pin, OPA is enabled.
Enable
000B
001B
010B
011B
100B
101B
1
PE0/AN0/OPO is OPA output pin and OPA output signal is input to
ADC channel 0, OPA is enabled.
000B
PE0/AN0/OPO is digital input/output pin, OPA is disabled.
PE0/AN0/OPO is ADC channel 0 input pin, OPA is disabled.
001B
010B
011B
100B
101B
Disable*
0, 1
Note: ²*² If the OPA configuration option is disabled, the OPAEN (bit 7 of OPAC) must not be set an unknown value will
be read.
Bit No.
Label
Function
0~3
AOF0~AOF3 Operational amplifier input offset voltage cancellation control bits
Operational amplifier input offset voltage cancellation reference selection bit
4
5
ARS
1/0: select OPP/OPN as the reference input
Input offset voltage cancellation mode and operational amplifier mode selection
AOFM
1/0: input offset voltage cancellation mode/operational amplifier mode
6
7
OPAOP
OPAEN
Operational amplifier output; positive logic. This bit is read only.
Operational amplifier enable/disable (1/0)
OPAC Register (Operational Amplifier Control Register)
S
S
1
2
O
P
P
A
R
S
A
O
F
M
S
1
S
2
S
3
0
0
1
1
0
1
0
1
O
N
O
O
O
N
N
N
O
O
F
F
F
P
E
0
/
A
N
0
S
3
O
F
F
O
O
N
N
O
P
N
O
O
N
N
F
A
O
F
0
~
A
O
F
3
O
F
F
O
P
A
E
N
P
E
0
/
A
N
0
/
O
P
O
OPA Block Diagram
Rev. 1.00
28
December 13, 2006
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
