lm3s811配合ch451控制数码管的显示

lm3s811配合ch451控制数码管的显示示例，昨天刚调出来的

// 定义全局的系统时钟变量
unsigned long TheSysClock = 12000000UL;
// 定义引脚
#define CH451_PERIPH   SYSCTL_PERIPH_GPIOD
#define CH451_PORT    GPIO_PORTD_BASE

//PD0-LOAD(上升沿发送命令)   PD1-DIN(输入)   PD2-DCLK(时钟)   PD3-DOUT(中断引脚EINT1)若只显示数码管不用键盘可不接这个引脚

void ch451write(unsigned int command)
{
    int i;
    signed int a;
   SysCtlDelay(50 * (TheSysClock / 3000)); // 延时约50ms
   GPIOPinWrite(CH451_PORT, GPIO_PIN_0 , 0);
    for(i=0;i<12;i++)
    {
        a=command&1;
        if(a==1)
        {
        GPIOPinWrite(CH451_PORT, GPIO_PIN_1 , 0xff);
         }
         else
         {
        GPIOPinWrite(CH451_PORT, GPIO_PIN_1 , 0x0);   //Din
         }
        GPIOPinWrite(CH451_PORT, GPIO_PIN_2 , 0x0);
        command>>=1;
        GPIOPinWrite(CH451_PORT, GPIO_PIN_2 , 0xff);   //Dclk
    }
       GPIOPinWrite(CH451_PORT, GPIO_PIN_0 , 0x01);    //Load   重要
}

void ch451_init()                                  
{
 SysCtlPeripheralEnable(CH451_PERIPH); // 使能CH451所在的GPIO端口
 GPIOPinTypeGPIOOutput(CH451_PORT, GPIO_PIN_0 | GPIO_PIN_1 | GPIO_PIN_2); // 设置CH451所在管脚为输出
 GPIOPinTypeGPIOInput(CH451_PORT, GPIO_PIN_3); // 设置CH451所在管脚为输入
 GPIOPinWrite(CH451_PORT, GPIO_PIN_1 , 0x00);      //先低后高选择4线输入
 GPIOPinWrite(CH451_PORT, GPIO_PIN_1 , 0xff);

 ch451write(0x201);            //复位
 ch451write(0x401);            //开显示
 ch451write(0x580);            //BCD译码方式

}

void show(int value)     
{
            ch451write(0x0800|(value%10));  //个位
            ch451write(0x0900|(value/10%10));  //十位
            ch451write(0x0a00|(value/100%10));  //百位
            ch451write(0x0b00|(value/1000));  //千位

}

主函数中调用ch451_init() 初始化和show（val）显示数值