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7.5 Port 5
7.5.1 Overview
Port 5 is a 4-bit input/output port with the pin configuration shown in figure 7-10. The pin functions
differ depending on the operating mode.
In mode 1, settings in the port 5 data direction register (P5DDR) designate pins for address bus
output (A
Port 5 has software-programmable built-in pull-up transistors.
Pins in port 5 can drive one TTL load and a 90-pF capacitive load. They can also drive a LED or a
darlington transistor pair.
7.5.2 Register Descriptions
Table 7-6 summarizes the registers of port 5.
Table 7-6 Port 5 Registers
Address*
H'FFC8
H'FFCA
H'FFDB
Note: * Lower 16 bits of the address.
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to A
) or generic input. In modes 2 and 3, port 5 is a generic input/output port.
19
16
Port 5
pins
P5 /A
3
19
P5 /A
2
18
Port 5
P5 /A
1
17
P5 /A
0
16
Figure 7-10 Port 5 Pin Configuration
Name
Port 5 data direction register
Port 5 data register
Port 5 input pull-up control register
Mode 1
Modes 2 and 3
P5 (input)/A
(output)
P5 (input/output)
3
19
P5 (input)/A
(output)
P5 (input/output)
2
18
P5 (input)/A
(output)
P5 (input/output)
1
17
P5 (input)/A
(output)
P5 (input/output)
0
16
Abbreviation
P5DDR
P5DR
P5PCR
134
3
2
1
0
R/W
Initial Value
W
H'F0
R/W
H'F0
R/W
H'F0
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