HD643303x Hitachi, HD643303x Datasheet - Page 154

• Manufacturer Part Number: HD643303x
• Description: Hitachi Microcomputer
• Manufacturer: Hitachi

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