Port Data Registers; Port Data Register Summary - Samsung S3F80JB User Manual

I/O PORTS

PORT DATA REGISTERS

Table 9-4 gives you an overview of the register locations of all four S3F80JB I/O port data registers. Data
registers for ports 0,1,2 and 4 have the general format shown in Figure 9-1.
The data register for port 3, P3, contains 6-bits for P3.0–P3.5, 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
Port 4 data register
Because port 3 is a 6–bit I/O port, the port 3 data register only contains values for P3.0 – P3.5. The P3 register
also contains a special carrier on/off bit (P3.7). See the port3 description for details. All other I/O ports are 8–bit.
9-4
Table 9-4. Port Data Register Summary
Mnemonic
P0
P1
P2
P3
P4
MSB .7 .6 .5
Pn.5
Pn.6
Pn.7
NOTE: Because port 3 is a 6-bit I/O port, the port 3 data register only
contains values for P3.0-P3.5.
The P3 register also contains a special carrier on/off bit (P3.7).
See the port 3 description for details.
All other S3F80JB I/O ports are 8-bit.
Figure 9-1. S3F80JB I/O Port Data Register Format
NOTE
Decimal Hex
224 E0H
225 E1H
226 E2H
227 E3H
228 E4H
.4 .3 .2 .1
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
Set 1, Bank 0
.0 LSB
Pn.0
S3F80JB
R/W
R/W
R/W
R/W
R/W
R/W