Table of Contents
Advertisement
ABWCR and P4DDR are not initialized in software standby mode. When port 4 functions as a
generic input/output port, if a P4DDR bit is set to 1, the corresponding pin maintains its output
www.DataSheet4U.com
state in software standby mode.
Port 4 Data Register (P4DR): P4DR is an 8-bit readable/writable register that stores output data
for pins P4
to P4
. When a bit in P4DDR is set to 1, if port 4 is read the value of the
7
0
corresponding P4DR bit is returned. When a bit in P4DDR is cleared to 0, if port 4 is read the
corresponding pin level is read.
Bit
P4
Initial value
Read/Write
R/W
P4DR is initialized to H'00 by a reset and in hardware standby mode. In software standby mode it
retains its previous setting.
Port 4 Input Pull-Up MOS Control Register (P4PCR): P4PCR is an 8-bit readable/writable
register that controls the MOS input pull-up transistors in port 4.
Bit
7
P4 PCR
7
Initial value
0
Read/Write
R/W
In mode 7 (single-chip mode), and in 8-bit bus mode in modes 1 to 6 (expanded modes), when a
P4DDR bit is cleared to 0 (selecting generic input), if the corresponding P4PCR bit is set to 1, the
input pull-up MOS transistor is turned on.
P4PCR is initialized to H'00 by a reset and in hardware standby mode. In software standby mode it
retains its previous setting.
7
6
5
P4
P4
7
6
5
0
0
0
R/W
R/W
6
5
P4 PCR
P4 PCR
6
5
0
0
R/W
R/W
Port 4 input pull-up MOS control 7 to 0
These bits control input pull-up MOS transistors built into port 4
4
3
P4
P4
P4
4
3
0
0
R/W
R/W
R/W
Port 4 data 7 to 0
These bits store data for port 4 pins
4
3
2
P4 PCR
P4 PCR
P4 PCR
4
3
2
0
0
0
R/W
R/W
R/W
257
2
1
0
P4
P4
2
1
0
0
0
0
R/W
R/W
1
0
P4 PCR
P4 PCR
1
0
0
0
R/W
R/W
Advertisement
Table of Contents
