UPD65 NEC [NEC], UPD65 Datasheet - Page 15

• Manufacturer Part Number: UPD65
• Description: 4-BIT SINGLE-CHIP MICROCONTROLLER FOR INFRARED REMOTE CONTROL TRANSMISSION
• Manufacturer: NEC [NEC]

3.1 K
can 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
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 During double pressing of a key, a high-level output and a low-level output may coincide with
b
0
-b
7
I/O
I/O
I/O
: In reading : In INPUT mode, the K
Port (P0)
In writing
port is an 8-bit input/output port for key scan output.
port contains the pull-down resistor, allowing pull-down in INPUT mode only.
each other at the K
low. Therefore, be careful when using the K
The K
voltage range (V
Bit
Name
I/O
port is so designed that, even when connected directly to V
: Data is written to the K
In OUTPUT mode, the K
b
K
DD
7
I/O7
I/O
= 2.0 to 3.6 V), no problem may occur.
port. To avoid this, the low-level output current of the K
b
K
6
I/O6
Table 3-2. K
Data Sheet U14380EJ2V0DS00
I/O
b
K
I/O
5
I/O5
I/O
pin’s state is read.
pin’s output latch regardless of INPUT or OUTPUT mode.
pin’s output latch contents are read.
b
K
I/O
4
I/O4
Port (P0)
I/O
port for purposes other than key scan output.
b
K
3
I/O3
b
K
2
I/O2
b
K
1
I/O1
DD
within the normal supply
b
K
0
I/O0
PD64A, 65
I/O
port is held
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