3069RF-ZTAT Datasheet, PDF (287/1003 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER

8.5 Port 4
8.5.1 Overview
Port 4 is an 8-bit input/output port also used for data bus, with the pin configuration shown in
figure 8.4. The pin functions differ depending on the operating mode.
In modes 1 to 5 (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 transistors.
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 Modes 1 to 5
Mode 7
P4₇ /D₇
P4₆ /D₆
P4₅ /D₅
P4₄ /D₄
P4₃ /D₃
P4₂ /D₂
P4₁ /D₁
P4₀ /D₀
P4₇ (input/output)/D₇ (input/output)
P4₆ (input/output)/D₆ (input/output)
P4₅ (input/output)/D₅ (input/output)
P4₄ (input/output)/D₄ (input/output)
P4₃ (input/output)/D₃ (input/output)
P4₂ (input/output)/D₂ (input/output)
P4₁ (input/output)/D₁ (input/output)
P4₀ (input/output)/D₀ (input/output)
P4₇ (input/output)
P4₆ (input/output)
P4₅ (input/output)
P4₄ (input/output)
P4₃ (input/output)
P4₂ (input/output)
P4₁ (input/output)
P4₀ (input/output)
Figure 8.4 Port 4 Pin Configuration
Rev. 5.0, 09/04, page 265 of 978