HD6433802H Datasheet, PDF (157/435 Pages) Hitachi Semiconductor – Single-Chip Microcomputer

8.3 Port 4
8.3.1 Overview
Port 4 is a 3-bit I/O port and 1-bit input port, configured as shown in figure 8.2.
Port 4
P4₃ /IRQ₀
P4₂ /TXD₃₂
P4₁ /RXD₃₂
P4₀ /SCK₃₂
Figure 8.2 Port 4 Pin Configuration
8.3.2 Register Configuration and Description
Table 8.5 shows the port 4 register configuration.
Table 8.5 Port 4 Registers
Name
Port data register 4
Port control register 4
Port mode register 2
Abbrev.
PDR4
PCR4
PMR2
R/W
Initial Value Address
R/W
H'F8
H'FFD7
W
H'F8
H'FFE7
R/W
—
H'FFC9
1. Port data register 4 (PDR4)
Bit
7
6
5
4
3
2
1
0
—
—
—
—
P4₃
P4 ₂
P4 ₁
P4 ₀
Initial value
1
1
1
1
1
0
0
0
Read/Write
—
—
—
—
R
R/W
R/W
R/W
PDR4 is an 8-bit register that stores data for port 4 pins P4₂ to P4₀. If port 4 is read while PCR4
bits are set to 1, the values stored in PDR4 are read, regardless of the actual pin states. If port 4 is
read while PCR4 bits are cleared to 0, the pin states are read.
Upon reset, PDR4 is initialized to H'F8.
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