UPD62A NEC, UPD62A Datasheet - Page 15

• Manufacturer Part Number: UPD62A
• Description: 4-BIT SINGLE-CHIP MICROCONTROLLER FOR INFRARED REMOTE CONTROL TRANSMISSION
• Manufacturer: NEC

3.1 K
be read in output mode.
The K
Input/output mode is set by bit 1 of the P4 register.
If a read instruction is executed, the pin state can be read in input mode, whereas the output latch contents can
If the write instruction is executed, data can be written to the output latch regardless of input or output mode.
When reset, the port is placed in output mode; and the value of the output latch (P0) becomes 1111 1111B.
The K
Caution If a key is double-pressed, a high-level output and a low-level output may coincide at the
b
0
to b
I/O
I/O
I/O
7
Port (P0)
: Read:
port is an 8-bit input/output port for key scan output.
port includes a pull-down resistor, allowing pull-down in input mode only.
Write:
K
careful when using the K
The K
voltage range (V
I/O
Bit
Name
port. To avoid this, the low-level output current of the K
I/O
port is so designed that, even when connected directly to V
In input mode, the K
In output mode, the K
Data is written to the K
b
K
DD
7
I/O7
= 2.0 to 3.6 V), no problem may occur.
b
K
I/O
6
I/O6
I/O
port for purposes other than key scan output.
I/O
Table 3-2. K
Data Sheet U14474EJ1V0DS00
I/O
pin’s state is read.
pin’s output latch contents are read.
pin’s output latch regardless of input or output mode.
b
K
5
I/O5
b
K
I/O
4
I/O4
Port (P0)
b
K
3
I/O3
b
K
2
I/O2
I/O
port is held low. Therefore, be
b
K
DD
1
I/O1
, within the normal supply
b
K
0
I/O0
PD62A
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