HD6413002 Datasheet, PDF (259/700 Pages) Renesas Technology Corp – High-performance single-chip microcontroller

9.2.3 Pin Functions in Each Mode
The functions of port 4 differ depending on whether 8-bit or 16-bit bus mode is selected by
ABWCR settings. The pin functions in each mode are described below.
8-Bit Bus Mode: Input or output can be selected separately for each pin in port 4. A pin becomes
an output pin if the corresponding P4DDR bit is set to 1 and an input pin if this bit is cleared to 0.
Figure 9-2 shows the pin functions in 8-bit bus mode. This is the initial state in modes 1 and 3.
Port 4
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 9-2 Pin Functions in 8-Bit Bus Mode (Port 4)
16-Bit Bus Mode: The input/output settings in P4DDR are ignored. Port 4 automatically becomes
a bidirectional data bus. Figure 9-3 shows the pin functions in 16-bit bus mode. This is the initial
state in modes 2 and 4.
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