MITSUBISHI MICROCOMPUTERS
4280 Group
SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER for INFRARED REMOTE CONTROL TRANSMITTERS
CONTROL REGISTERS
Timer control register V1
at reset : 0002
at RAM back-up : 0002
W
0
1
0
1
0
1
Auto-control output by timer 1 is invalid
Auto-control output by timer 1 is valid
Carrier output (CARRY)
V12
V11
V10
Carrier wave output auto-control bit
Timer 1 count source selection bit
Timer 1 control bit
Bit 5 of watchdog timer (WDT)
Stop (Timer 1 state retained)
Operating
Pull-down control register PU0
Port D7 pull-down control bit
at reset : 0002
at RAM back-up : state retained
W
0
1
0
1
0
1
Pull-down transistor OFF, input circuit OFF, key-on wakeup invalid
Pull-down transistor ON, input circuit ON, key-on wakeup valid
Pull-down transistor OFF, key-on wakeup invalid
Pull-down transistor ON, key-on wakeup valid
PU02
PU01
PU00
Port E1 pull-down control bit
Port E0 pull-down control bit
Pull-down transistor OFF, key-on wakeup invalid
Pull-down transistor ON, key-on wakeup valid
Carrier wave selection register C
at reset : 1112
C2 C1 C0
at RAM back-up : 1112
Carrier wave
R/W
Frequency
Duty
C2
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
System clock/12
System clock/12
System clock/8
System clock/8
System clock
1/3
1/2
1/4
1/2
1/2
C1
C0
Carrier wave selection bits
No carrier wave
“L” level fixed
f(XIN)/4 (Note 2)
1/2
Logic operation selection register LO
Logic operation selection bits
at reset : 002
W
at RAM back-up : 002
L
O
1 L
O
0
1
0
1
0
Logic operation function
Exclusive logic OR operation (XOR)
0
LO1
LO0
0
1
1
OR operation (OR)
AND operation (AND)
Not available
Notes 1: “R” represents read enabled, and “W” represents write enabled.
2: f(XIN) is valid only when f(XIN)/8 is selected as the system clock.
MITSUBISHI
ELECTRIC
36
MITSUBISHI [ Mitsubishi Group ]
