Samsung SCX-1150F Repair Manual page 41

CIRCUIT DESCRIPTION
3-10 I/O PORT configuration and use usage
It has 32 I/O Ports, and 24 Ports of them are arranged to decide I/O direction with Software Control, and the rest 8 Ports are
arranged to be used for Input or Output only. All of I/O Ports are classified into four Blocks according to the characteristics of
I/O Control, and each Block consists of 8 Ports.
Type I/O Control
PA X Byte Control
PB X Byte Control
PC X Byte Control
PD X Byte Control
1) Assignment of Port PAX
-. PA0 : RESERVED
-. PA1 : LED 1
-. PA2 : RESERVED
-. PA3 : RESERVED
-. PA4 : RESERVED
-. PA5 : RESERVED
-. PA6 : RESERVED
-. PA7 : RESERVED
2) Assignment of port PBX
-. PB0(Output) : LCD Enable
-. PB1(Output) : LCD R/W
-. PB2(Output) : LCD RS
-. PB3(Input) : GND
-. PB4(Input) : Unused (Pull-up)
-. PB5(Input) : GND
-. PB6(Output) : UART TXD in Main UART
-. PB7(Input) : UART RXD from Main UART
Repair Manual
3-38
I/O direction USE
I/O => Output LED Control
In : 4, Out : 4 UART, LCD, Sensor
I/O => Input Key Input
I/O => Output LCD Data, Key Scan
Remarks
Samsung Electronics