在网上看了下编写上位机的例子，通过发送16进制的指令控制相对应的IO口的开关状态，可是编写C语言里面LPC1114这个库函数实验的例子没有讲解关于下位机通讯协议的内容及头文件的编写

比如我想要通过下位机 接收的时候先将头码屏蔽然后直接接收功能码 或者取出Byte里面取出功能码的数值去执行不知道这个C代码要怎么写，请各位哥哥指教！！先谢谢了，我编写的代码如下

#include <lpc11xx.h>
#include "LCD22.h"
#include <stdio.h>
#include "systick_delay.h"
#include "gpio.h"



#ifndef CONFIG_ENABLE_DRIVER_ADC
#define CONFIG_ENABLE_DRIVER_ADC    1
#endif

#include "adc.h"
#include "uart.h"

#define Open_ADC0
#define head 0x00
void GPIO_Configuration(void);





int main(void)


{
        uint8_t byte;
        uint8_t byte1;
        
        
  char  a[8];
        int i;

  delay_ms(1000);
        
        UART_init(9600); // 串口，并设置波特率
        ADCInit( ADC_CLK );
        LCD_Initializtion();
        GPIO_Configuration();
/************************************************/
/* 函数功能：串口接收字节数据                       */
/************************************************/
uint8_t UART_recive(void)
{   
    while(!(LPC_UART->LSR & (1<<0)));//等待接收到数据
    return(LPC_UART->RBR);             //读出数据
}

/************************************************/

        
        while(1)
    {
                  byte=UART_recive();           // 等待接收数据
                  delay_ms(5000);
                        byte1=byte-0x00;  //这个应该是错的，我想去掉头码，取功能码
                        printf("%c: ASCII= %d\r\n",byte,byte);
                        
               
                        
                        printf("%c: ASCII= %d\r\n",byte1,byte1);
         
                        
                        
                        i=0;
                        if(i<2000&&byte==head)
                        {
                                i++;
                                
                                        switch(byte1)                                       
                                
                                        {
                                                case 0x01 : GPIOSetValue(PORT2,4,HIGH);break;//lED1 路关  上位机发送0x00 (头码） 0x01（功能码）
                                                case 0x81 : GPIOSetValue(PORT2,4,LOW);break;//lED1 路开
                                                case 0x02 : GPIOSetValue(PORT2,5,HIGH);break;//lED2 路关
                                                case 0x82 : GPIOSetValue(PORT2,5,LOW);break;//lED2 路开
                                                case 0x03 : GPIOSetValue(PORT2,6,HIGH);break;//lED3 路关
                                                case 0x83 : GPIOSetValue(PORT2,6,LOW);break;//lED3 路开
                                                case 0x04 : GPIOSetValue(PORT2,7,HIGH);break;//lED4 路关
                                                case 0x84 : GPIOSetValue(PORT2,7,LOW);break;//lED4 路开
                                                case 0x85 : GPIOSetValue(PORT2,4,HIGH);GPIOSetValue(PORT2,5,HIGH); GPIOSetValue(PORT2,6,HIGH); GPIOSetValue(PORT2,7,HIGH);break;//全局关
                                                case 0x95 : GPIOSetValue(PORT2,4,LOW);GPIOSetValue(PORT2,5,LOW); GPIOSetValue(PORT2,6,LOW); GPIOSetValue(PORT2,7,LOW);break;//全局开
                                                default :break;
                                        }
                                }
                        delay_ms(2000);
                        printf("Use the welcome Open1114 development board!\r\n");

                                 #ifdef        Open_ADC0
                                         printf("ADC Channel%d=%d\r\n",0,ADCRead(0));
                                        sprintf(a,"%10.7f",(ADCRead(0)*3.3)/1024);
                                         #endif
                                 
                                        delay_ms(500);
                                        GUI_Text(50,140,a,White,Red);
                                
                                
                                        GUI_Text(0,220,"Welcome Open1114",White,Red);   
                                        GUI_Text(0,236,"--jason",White,Red);  

                                        LCD_Drawcircle(120,70,40,Blue);
                                        LCD_Drawcircle(120,70,39,Blue);
                                        LCD_DrawLine(0,120,239,120,Blue);
                                        LCD_DrawLine(0,121,239,121,Blue);
}
}
void GPIO_Configuration(void)
{
        /* LED0(PIO2_7)  LED0(PIO2_6)  LED0(PIO2_5)  LED0(PIO2_4) */
        GPIOSetDir(PORT2,4,OUT);
        GPIOSetDir(PORT2,5,OUT);
        GPIOSetDir(PORT2,6,OUT);
        GPIOSetDir(PORT2,7,OUT);