HD6473032F Datasheet, PDF (154/572 Pages) Hitachi Semiconductor – Hitachi Microcomputer

7.6 Port 6
7.6.1 Overview
Port 6 is a 4-bit input/output port that is also used for input and output of bus control signals (WR,
RD, AS, and WAIT).
Figure 7-13 shows the pin configuration of port 6. In mode 1, the pin functions are WR, RD, AS,
and P6₀/WAIT. In modes 2 and 3, port 6 is a generic input/output port.
Pins in port 6 can drive one TTL load and a 90-pF capacitive load. They can also drive a darlington
transistor pair.
Port 6
Port 6 pins
P6 ₅ / WR
P6 ₄ / RD
P6 ₃ / AS
P6 ₀ / WAIT
Modes 1
WR (output)
RD (output)
AS (output)
P6 (input/output)/WAIT (input)
Modes 2 and 3
P6 ₅ (input/output)
P6 ₄ (input/output)
P6 ₃ (input/output)
P6 ₀ (input/output)
Figure 7-13 Port 6 Pin Configuration
7.6.2 Register Descriptions
Table 7-8 summarizes the registers of port 6.
Table 7-8 Port 6 Registers
Address* Name
H'FFC9
Port 6 data direction register
H'FFCB
Port 6 data register
Note: * Lower 16 bits of the address.
Abbreviation R/W
P6DDR
W
P6DR
R/W
Initial Value
H'80
H'80
139