9.6 Port 5
9.6.1 Overview
Port 5 is a 4-bit input/output port with the pin configuration shown in figure 9-5. The pin functions
differ depending on the operating mode.
In modes 1 to 4 (expanded modes with on-chip ROM disabled), port 5 consists of address output
pins (A
19
to A
16
). In modes 5 and 6 (expanded modes with on-chip ROM enabled), settings in the
port 5 data direction register (P5DDR) designate pins for address bus output (A
19
to A
16
) or
generic input. In mode 7 (single-chip mode), port 5 is a generic input/output port.
Port 5 has software-programmable built-in pull-up MOS transistors.
Pins in port 5 can drive one TTL load and a 90-pF capacitive load. They can also drive an LED or
a darlington transistor pair.
Figure 9-5 Port 5 Pin Configuration
9.6.2 Register Descriptions
Table 9-8 summarizes the registers of port 5.
Table 9-8 Port 5 Registers
Initial Value
Address
*
Name
Abbreviation
R/W
Modes 1 to 4
Modes 5 to 7
H'FFC8
Port 5 data direction register
P5DDR
W
H'FF
H'F0
H'FFCA
Port 5 data register
P5DR
R/W
H'F0
H'F0
H'FFDB
Port 5 input pull-up MOS
P5PCR
R/W
H'F0
H'F0
control register
Note:
*
Lower 16 bits of the address.
Port 5
P5 /A
P5 /A
P5 /A
P5 /A
3
2
1
0
19
18
17
16
A (output)
A (output)
A (output)
A (output)
19
18
17
16
P5 (input)/A (output)
P5 (input)/A (output)
P5 (input)/A (output)
P5 (input)/A (output)
3
2
1
0
Port 5
pins
Modes 1 to 4
Modes 5 and 6
P5 (input/output)
P5 (input/output)
P5 (input/output)
P5 (input/output)
3
2
1
0
Mode 7
19
18
17
16
259
www.DataSheet4U.com