User’s Manual
C166S V1 SubSystem
Parallel Ports
User’s Manual
7-10
V 1.6, 2001-08
7.4
Port 4
If this 8-bit port is used for general purpose IO, the direction of each line can be
configured via the corresponding direction register DP4.
Alternate Functions of Port 4
During external bus cycles that use segmentation (i.e. an address space above
64 KByte) a number of Port 4 pins may output the segment address lines. The number
of pins that is used for segment address output determines the external address space
which is directly accessible. The other pins of Port 4 (if any) may be used for general
purpose IO.
If segment address lines are selected, the alternate function of Port 4 may be necessary
to access e.g. external memory directly after reset. For this reason Port 4 will be
switched to this alternate function automatically.
The number of segment address lines is selected via conf_rst_salsel_i[1:0] (SALSEL)
during reset.
P4
3RUW'DWD5HJLVWHU
SFR (FFC8
H
/E4
H
)
Reset Value: - - 00
H
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
P4.7 P4.6 P4.5 P4.4 P4.3 P4.2 P4.1 P4.0
-
-
-
-
-
-
-
-
rw
rw
rw
rw
rw
rw
rw
rw
Bit
Function
P4.y
Port data register P4 bit y
DP4
P4 Direction Ctrl. Register
SFR (FFCA
H
/E5
H
)
Reset Value: - - 00
H
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DP4
.7
DP4
.6
DP4
.5
DP4
.4
DP4
.3
DP4
.2
DP4
.1
DP4
.0
-
-
-
-
-
-
-
-
rw
rw
rw
rw
rw
rw
rw
rw
Bit
Function
DP4.y
Port direction register DP4 bit y
DP4.y = 0: Port line P4.y is an input (high-impedance)
DP4.y = 1: Port line P4.y is an output
Содержание C166S V1 SubSystem
Страница 10: ...User s Manual C166S V1 SubSystem User s Manual I 6 V 1 6 2001 08...
Страница 16: ...User s Manual C166S V1 SubSystem Introduction User s Manual 1 6 V 1 6 2001 08...
Страница 126: ...User s Manual C166S V1 SubSystem Central Processing Unit User s Manual 3 96 V 1 6 2001 08...
Страница 178: ...User s Manual C166S V1 SubSystem Memory Organization User s Manual 4 52 V 1 6 2001 08...
Страница 206: ...User s Manual C166S V1 SubSystem Instruction Set User s Manual 5 28 V 1 6 2001 08...
Страница 306: ...User s Manual C166S V1 SubSystem Detailed Instruction Set User s Manual 6 100 V 1 6 2001 08...
Страница 362: ...User s Manual C166S V1 SubSystem The External Bus Interface User s Manual 8 40 V 1 6 2001 08...
Страница 452: ...User s Manual C166S V1 SubSystem General Purpose Timer Unit User s Manual 12 44 V 1 6 2001 08...
Страница 454: ...User s Manual C166S V1 SubSystem Instruction Index User s Manual 13 2 V 1 6 2001 08...
Страница 459: ......