HD6433044 Hitachi Semiconductor, HD6433044 Datasheet - Page 268

• Manufacturer Part Number: HD6433044
• Description: (HD64 Series) Hitachi Single-Chip Microcomputer
• Manufacturer: Hitachi Semiconductor

9.5 Port 4
9.5.1 Overview
Port 4 is an 8-bit input/output port with the pin configuration shown in figure 9-4. The pin
functions differ according to the operating mode.
In modes 1 to 6 (expanded modes), when the bus width control register (ABWCR) designates
areas 0 to 7 all as 8-bit-access areas, the chip operates in 8-bit bus mode and port 4 is a generic
input/output port. When at least one of areas 0 to 7 is designated as a 16-bit-access area, the chip
operates in 16-bit bus mode and port 4 becomes part of the data bus. In mode 7 (single-chip
mode), port 4 is a generic input/output port.
Port 4 has software-programmable built-in pull-up MOS.
Pins in port 4 can drive one TTL load and a 90-pF capacitive load. They can also drive a
darlington transistor pair.
Port 4
Port 4 pins
P4 /D
P4 /D
P4 /D
P4 /D
P4 /D
P4 /D
P4 /D
P4 /D
7
6
5
4
3
2
1
0
Figure 9-4 Port 4 Pin Configuration
7
6
5
4
3
2
1
0
Modes 1 to 6
P4 (input/output)/D
P4 (input/output)/D
P4 (input/output)/D
P4 (input/output)/D
P4 (input/output)/D
P4 (input/output)/D
P4 (input/output)/D
P4 (input/output)/D
7
6
5
4
3
2
1
0
255
7
6
5
4
3
2
1
0
(input/output)
(input/output)
(input/output)
(input/output)
(input/output)
(input/output)
(input/output)
(input/output)
Mode 7
P4 (input/output)
P4 (input/output)
P4 (input/output)
P4 (input/output)
P4 (input/output)
P4 (input/output)
P4 (input/output)
P4 (input/output)
7
6
5
4
3
2
1
0