S3C2440A has 130 multi-functional input/output port pins and there are eight ports as shown below:
    - Port A(GPA): 25-output port
    - Port B(GPB): 11-input/out port
    - Port C(GPC): 16-input/output port
    - Port D(GPD): 16-input/output port
    - Port E(GPE): 16-input/output port
    - Port F(GPF): 8-input/output port
    - Port G(GPG): 16-input/output port
    - Port H(GPH): 9-input/output port
    - Port J(GPJ): 13-input/output port
    端口控制描述
    端口控制寄存器(GPACON-GPJCON)
    端口數據寄存器(GPADAT-GPJDAT)
    端口上拉寄存器(GPBUP-GPJUP)
    復用控制寄存器
    外部中斷控制寄存器
    假設，有4個LED燈，分別接在GPF0~GPF3上，低電平點亮
    GPF有7個I/O口，三組寄存器GPFCON，GPFDAT，GPFUP
    //包含頭文件區
    #include "2440addr.h" //系統文件
    #include "2440lib.h"
    #include "def.h"
    #include "uart.h"
    void Main(){
    //步，設置系統時鐘
    memcpy((unsigned char *)0x0,(unsigned char *)0x30000000,1000);
    //調用2440lib.c中的函數
    SetSysFclk(FCLK_200M);//設置系統時鐘為200M
    ChangeClockDivider(1,1);//設置分頻為1:2:4
    CalcBusClk(); //計算總線頻率
    //第二步：初始化串口
    Uart_Select(0);
    Uart_Init(0,115200);
    //第三步：配置GPF寄存器
    rGPFCON = (rGPFCON | 0xffff) & 0xffffff55; //設置GPF為輸出口
    rGPFUP &= 0xfff0; //使能上拉
    rGPFDAT = 0xff; //初始化
    //第四步：進入大循環
    while(1){
    rGPFDAT = 0xFE; //點亮
    }
    }