UPD17073 NEC, UPD17073 Datasheet - Page 63

• Manufacturer Part Number: UPD17073
• Description: 4-BIT SINGLE-CHIP MICROCONTROLLER WITH HARDWARE FOR DIGITAL TUNING SYSTEM
• Manufacturer: NEC

10.3.2 Using input port
SKT instruction).
read when the low level is input.
resistor is connected or disconnected is specified by the port 1A pull-down resistor select register.
reset
At
The input data can be read by executing an instruction that reads the contents of the port register P1A (such as
“1” is read from each bit of the port register when the high level is input to the corresponding port pin, and “0” is
Nothing is changed even if a write instruction (such as MOV) is executed to the port register.
Port 1A can be connected to or disconnected from a pull-down resistor bitwise by software. Whether the pull-down
Figure 10-1 shows the configuration and function of the port 1A pull-down resistor select register.
resistor select register
Port 1A pull-down
Power-ON
Clock stop
CE
Name
Figure 10-1. Configuration of Port 1A Pull-Down Resistor Select Register
b
A
D
P
1
P
L
3
0
1
0
3
Flag symbol
Retained
Retained
b
A
D
P
P
L
0
1
1
2
0
2
b
A
D
P
1
P
L
1
0
1
0
1
b
A
D
P
P
L
0
1
1
0
0
0
Pull-down resistor ON
Pull-down resistor OFF
Pull-down resistor ON
Pull-down resistor OFF
Pull-down resistor ON
Pull-down resistor OFF
Pull-down resistor ON
Pull-down resistor OFF
(BANK1)
Address
53H
Selects ON/OFF of pull-down resistor of P1A2/AD0 pin
Selects ON/OFF of pull-down resistor of P1A3/AD1 pin
Selects ON/OFF of pull-down resistor of P1A0 pin
Selects ON/OFF of pull-down resistor of P1A1 pin
Read/
Write
R/W
PD17072,17073
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