Samsung S3C9228/P9228 사용자 설명서
I/O PORTS
S3C9228/P9228
9-14
PORT 4
Port 4 is an 8-bit I/O port with individually configurable pins. Port 4 pins are accessed directly by writing or
reading the port 4 data register, P4 at location E8H in page 0. P4.0-P4.7 can serve as inputs or as push-pull,
open-drain outputs. You can configure the following alternative functions with LCD port control register, LPOT:
reading the port 4 data register, P4 at location E8H in page 0. P4.0-P4.7 can serve as inputs or as push-pull,
open-drain outputs. You can configure the following alternative functions with LCD port control register, LPOT:
— Low-nibble pins (P4.0-P4.3): SEG4-SEG7
— High-nibble pins (P4.4-P4.7): SEG8-SEG11
Port 4 Control Registers (P4CONH, P4CONL)
Port 4 has two 8-bit control registers: P4CONH for P4.4-P4.7 and P4CONL for P4.0-P4.3. A reset clears the
P4CONH and P4CONL registers to "00H", configuring all pins to input mode. You use control registers setting to
select input or output mode.
P4CONH and P4CONL registers to "00H", configuring all pins to input mode. You use control registers setting to
select input or output mode.
Port 4 Control Register, High Byte (P4CONH)
F9H, Page 0, R/W
.7
.6
.5
.4
.3
.2
.1
.0
MSB
LSB
P4.5/SEG9
P4.4/SEG8
P4CONH bit-pair pin configuration settings:
00
01
10
11
N-channel open-drain output mode
Input mode with pull-up
Push-pull output mode
Input mode
P4.6/SEG10
P4.7/SEG11
Figure 9-19. Port 4 High-Byte Control Register (P4CONH)
Port 4 Control Register, Low Byte (P4CONL)
FAH, Page 0, R/W
.7
.6
.5
.4
.3
.2
.1
.0
MSB
LSB
P4.1/SEG5
P4.0/SEG4
P4CONL bit-pair pin configuration settings:
00
01
10
11
N-channel open-drain output mode
Input mode with pull-up
Push-pull output mode
Input mode
P4.2/SEG6
P4.3/SEG7
Figure 9-20. Port 4 Low-Byte Control Register (P4CONL)