Port Data Registers - Samsung S3F80P5X User Manual

S3F80P5_UM_ REV1.00

PORT DATA REGISTERS

Table 9-4 gives you an overview of the register locations of all four S3F80P5 I/O port data registers. Data
registers for ports 0,1 have the general format shown in Figure 9-1.
The data register for port 3, P3, contains 2-bits for P3.0−P3.1, and an additional status bit (P3.7) for
carrier signal on/off.
Register Name
Port 0 data register
Port 1 data register
Port 2 data register
Port 3 data register
Because port 3 is a 2-bit I/O port, the port 3 data register only contains values for P3.0 − P3.1. The P3 register
also contains a special carrier on/off bit (P3.7). See the port3 description for details. All other I/O ports except P2
are 8-bit.
Table 9-2. Port Data Register Summary
Mnemonic
P0
P1
P2
P3
MSB .7 .6 .5
Pn.5
Pn.6
Pn.7
NOTE: Because port 3 is a 2-bit I/O port, the port 3 data register only
contains values for P3.0-P3.1.
The P3 register also contains a special carrier on/off bit (P3.7).
See the port 3 description for details.
Figure 9-1. S3F80P5 I/O Port Data Register Format
NOTE
Decimal Hex
224 E0H
225 E1H
226 E2H
227 E3H
.4 .3 .2
Pn.1
Pn.2
Pn.3
Pn.4
Location
Set 1, Bank 0
Set 1, Bank 0
Set 1, Bank 0
Set 1, Bank 0
.1 .0 LSB
Pn.0
I/O PORTS
R/W
R/W
R/W
R/W
R/W
9-3