PD62A_15 Datasheet, PDF (18/64 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLER FOR INFRARED REMOTE CONTROL TRANSMISSION

µPD62A
3.2 KI Port/Special Ports (P1)
3.2.1 KI port (P11: bits 4 to 7 of P1)
The KI port is a 4-bit input port for key entry.
The pin status can be read at this port.
Software can be used to set whether to connect a pull-down resistor at the KI port in 4-bit units by means of bit
5 of the P4 register.
When reset, a pull-down resistor is connected.
Table 3-3. KI/Special Port Register (P1)
Bit
Name
b7
b6
b5
b4
b3
b2
KI3
KI2
KI1
KI0
S1/LED S0
b1
b0
(Fixed to 1)
b2:
b3:
b4 to b7:
In input mode, the status of the S0 pin is read (Read only).
In OFF mode, this bit is fixed to 1.
The status of the S1/LED pin is read regardless of input/output mode (Read only).
The status of the KI pin is read (Read only).
Caution In order to prevent malfunction, be sure to input a low level to more than one of pins KI0 to KI3
when reset is released (when the RESET pin changes from low level to high level, or POC is
released due to supply voltage startup).
3.2.2 S0 port (bit 2 of P1)
The S0 port is the input/OFF mode port.
The pin status can be read by setting this port to input mode with bit 0 of the P4 register.
In input mode, software can be used to set whether to connect a pull-down resistor at the S0 and S1/LED ports
in 2-bit units by means of bit 4 of the P4 register.
If input mode is canceled (set to OFF mode), the pin becomes high-impedance, but the through current is stopped
from flowing internally. In OFF mode, “1” can be read regardless of the pin status.
When reset, this port is set to OFF mode and becomes high-impedance.
3.2.3 S1/LED (bit 3 of P1)
The S1/LED port is an input/output port.
This port is set input or output mode by means of bit 2 of the P4 register. The pin status can be read in both
input and output mode.
In input mode, software can be used to set whether to connect a pull-down resistor at the S0 and S1/LED ports
in 2-bit units by means of bit 4 of the P4 register.
In output mode, the pull-down resistor is automatically disconnected, and this port becomes the remote control
transmission display pin (refer to 4. TIMER).
When reset, this port is placed in output mode, and a high level is output.
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Data Sheet U14474EJ2V0DS00