HD643303x Hitachi, HD643303x Datasheet - Page 165

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

7.9 Port 9
7.9.1 Overview
Port 9 is a 3-bit input/output port that is also used for input and output (TxD, RxD, SCK) by serial
communication interface (SCI), and for IRQ
operating modes. Figure 7-18 shows the pin configuration of port 9.
Pins in port 9 can drive one TTL load and a 30-pF capacitive load. They can also drive a darlington
transistor pair.
7.9.2 Register Descriptions
Table 7-13 summarizes the registers of port 9.
Table 7-13 Port 9 Registers
Address*
H'FFD0
H'FFD2
Note: * Lower 16 bits of the address.
Name
Port 9 data direction register
Port 9 data register
Port 9
Figure 7-18 Port 9 Pin Configuration
Port 9 pins
P9
P9
P9
4
2
0
(input/output)/SCK (input/output)/IRQ
(input/output)/RxD (input)
(input/output)/TxD (output)
4
input. Port 9 has the same set of pin functions in all
150
Abbreviation
P9DDR
P9DR
R/W
W
R/W
4
(input)
Initial Value
H'C0
H'C0