程序代码：

#define GPCCON      (*(volatile unsigned long *)0x56000020)
#define GPCDAT      (*(volatile unsigned long *)0x56000024)

#define GPC5_OUT    (1<<(5*2))
#define GPC6_OUT    (1<<(6*2))
#define GPC7_OUT    (1<<(7*2))

void wait (unsigned long ys)
{
    for(;ys > 0;ys-- );
}

int main(void)
{
    unsigned long i = 0;

    GPCCON = GPC5_OUT|GPC6_OUT|GPC7_OUT;

    while(1)
    {
        wait(30000);
        GPCDAT = (~(i<<5));
        if++i ==8)
          i = 0;
    }
    return 0;
}