UPD62A View Datasheet(PDF) - NEC => Renesas Technology

Part Name

Description

Manufacturer

UPD62A

4-BIT SINGLE-CHIP MICROCONTROLLER FOR INFRARED REMOTE CONTROL TRANSMISSION

NEC => Renesas Technology 

µPD62A

3.1 KI/O Port (P0)

The KI/O port is an 8-bit input/output port for key scan output.

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

be read in output mode.

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 KI/O port includes a pull-down resistor, allowing pull-down in input mode only.

Caution If a key is double-pressed, a high-level output and a low-level output may coincide at the

KI/O port. To avoid this, the low-level output current of the KI/O port is held low. Therefore, be

careful when using the KI/O port for purposes other than key scan output.

The KI/O port is so designed that, even when connected directly to VDD, within the normal supply

voltage range (VDD = 2.0 to 3.6 V), no problem may occur.

Bit

Name

Table 3-2. KI/O Port (P0)

b7

KI/O7

b6

KI/O6

b5

KI/O5

b4

KI/O4

b3

KI/O3

b2

KI/O2

b1

KI/O1

b0

KI/O0

b0 to b7: Read:

Write:

In input mode, the KI/O pin’s state is read.

In output mode, the KI/O pin’s output latch contents are read.

Data is written to the KI/O pin’s output latch regardless of input or output mode.

Data Sheet U14474EJ1V0DS00

15

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