Samsung S3P80C5 User Manual page 213

I/O PORTS
PORT DATA REGISTERS
Table 9-2 gives you an overview of the register locations of all three S3C80C5/C80C8 port data registers. Data
registers for ports 0, and 1 have the general format.
The data register for port 2, P2, contains three bits for P2.0, P2.1 and P2.2, and an additional status bit
for carrier signal on/off.
Register Name
Port 0 data register
Port 1 data register
Port 2 data register
Because port 2 is a 3-bit I/O port, the port 2 data register only contains values for P2.0, P2.1 and P2.2. The P2
register also contains values for P2.0, P2.1 and P2.2. The P2 register also contains a special carrier on/off
bit(P2.5). See the port 2 description for details. All other S3P80C5/C80C5/C80C8 I/O ports are 8-bit.
PULL-UP RESISTOR ENABLE REGISTERS
NOTE:
Figure 9-1. S3P80C5/C80C5/C80C8 I/O Port 0 Data Register Format
9-2
Table 9-2. Port Data Register Summary
Mnemonic
P0
P1
P2
Port0 Pull-up Resistor Enable Register (P0PUR)
MSB .7 .6 .5
P0.7 P0.6 P0.5
Pull-up resistor enable bit:
0 = Enable pull-up resistor
1 = Disable pull-up resistor
Pull-up resistors can be assigned to the port 2 pins, P2.0, P2.1 and
P2.2 by marking the appropriate the port 2 control register,P2CON.
NOTE
Decimal
224
225
226
E7H, R/W
.4 .3 .2 .1
P0.4 P0.3 P0.2 P0.1 P0.0
S3P80C5/C80C5/C80C8
Hex
E0H
E1H
E2H
.0 LSB
R/W
R/W
R/W
R/W