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4 port 4, 1 port 4 data direction register (p4ddr), 2 port 4 data register (p4dr) – Renesas H8S/2111B User Manual

Page 141

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Rev. 1.00, 05/04, page 107 of 544

7.4 Port

4

Port 4 is an 8-bit I/O port. Port 4 pins also function as TMR_0 and TMR_1 I/O pins, and the IIC_1
I/O pin. The output type of P42 is NMOS push-pull output. The output type of SDA1 is NMOS
open-drain output. Port 4 has the following registers.

• Port 4 data direction register (P4DDR)
• Port 4 data register (P4DR)

7.4.1

Port 4 Data Direction Register (P4DDR)

P4DDR specifies input or output for the pins of port 4 on a bit-by-bit basis.

Bit Bit

Name

Initial
Value R/W Description

7 P47DDR

0 W

6 P46DDR

0 W

5 P45DDR

0 W

4 P44DDR

0 W

3 P43DDR

0 W

2 P42DDR

0 W

1 P41DDR

0 W

0 P40DDR

0 W

When a bit in P4DDR is set to 1, the corresponding pin
functions as an output port, and when cleared to 0, as
an input port.

7.4.2

Port 4 Data Register (P4DR)

P4DR stores output data for port 4.

Bit Bit

Name

Initial
Value

R/W Description

7 P47DR

0 R/W

6 P46DR

0 R/W

5 P45DR

0 R/W

4 P44DR

0 R/W

3 P43DR

0 R/W

2 P42DR

0 R/W

1 P41DR

0 R/W

0 P40DR

0 R/W

If a port 4 read is performed while P4DDR bits are set
to 1, the P4DR values are read directly, regardless of
the actual pin states. If a port 4 read is performed while
P4DDR bits are cleared to 0, the pin states are read.

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