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S3C84E5/C84E9/P84E9 I/O PORTS
9-5
PORT 1
Port 1 is a 6-bit I/O port with individually configurable pins that you can use two ways:
— General-purpose digital I/O
— Alternative function: TAOUT, T1OUT0, T1CK0, BZOUT, TXD, RXD
Port 1 is accessed directly by writing or reading the port 1 data register, P1 at location E1H in set 1, bank 0.
Port 1 Control Register (P1CONH, P1CONL)
Port 1 has two 6-bit control registers: P1CONH for P1.4–P1.5 and P1CONL for P1.0–P1.3. A reset clears the
P1CONH and P1CONL registers to “00H”, configuring all pins to input modes. You use control registers settings to
select input or output mode (push-pull) and enable the alternative functions.
When programming the port, please remember that any alternative peripheral I/O function you configure using the
port 1 control registers must also be enabled in the associated peripheral module.
Port 1 Control Register, High Byte (P1CONH)
E8H, Set1, Bank0, R/W, Reset value="00"
.7 .6 .5 .4 .3 .2 .1 .0MSB LSB
[.7-.4] Not used
(must keep always 0)
[.3-.2] P1.5/TXD Configuration Bits
0 0 = Input mode with pull-up
0 1 = Input mode
1 0 = Push-pull output mode
1 1 = Alternative function mode: TXD output
[.1-.0] P1.4/RXD Configuration Bits
0 0 = Input mode with pull-up; RXD input
0 1 = Input mode; RXD input
1 0 = Push-pull output mode
1 1 = Alternative function mode: RXD output
Figure 9-3. Port 1 High-Byte Control Register (P1CONH)