Samsung S3C84E5 user manual Port 1 Control Register P1CONH, P1CONL, P1.5/TXD Configuration Bits

S3C84E5/C84E9/P84E9 I/O PORTS

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"

MSB

.7

.6

.5

.4

.3

.2

.1

.0

LSB

[.7-.4] Not used (must keep always 0)

[.3-.2] P1.5/TXD Configuration Bits

00 = Input mode with pull-up

01 = Input mode

10 = Push-pull output mode

1 1 = Alternative function mode: TXD output

[.1-.0] P1.4/RXD Configuration Bits

00 = Input mode with pull-up; RXD input

01 = Input mode; RXD input

10 = Push-pull output mode

1 1 = Alternative function mode: RXD output

Figure 9-3. Port 1 High-Byte Control Register (P1CONH)

9-5