149
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 7-16 shows the pin configuration of port 6. In modes 1, 3, 5, and 6 the pin functions are
WR
,
RD
,
AS
, and P6
0
/
WAIT
. In mode 7, 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
P6 /
P6 /
P6 /
P6 /
5
4
3
0
WR
RD
AS
WAIT
Port 6 pins
WR
RD
AS
P6
0
Modes 1, 3, 5 and 6
P6
P6
P6
P6
5
4
3
0
Mode 7
(input/output)
(input/output)
(input/output)
(input/output)
(output)
(output)
(output)
(input/output)/WAIT (input)
Figure 7-16 Port 6 Pin Configuration
7.6.2 Register Descriptions
Table 7-8 summarizes the registers of port 6.