并口定义及其编程基础之四：IIC调试工具的命令解析及使用

（1）很多时候我们使用一个软件调试工具时，里面都约定有特定的命令格式来方便使用。此时，程序一般要先对特定格式的命令进行解析（parse），再分解成组合命令来执行。假设一个单步I2C调试工具中，在命令行中输入可用命令，有如下约定：

>>command for START:
start
s
[

>>command for STOP:
stop
st
]

>>command for WRITE:
write data
w data
> data

 

>>command for READ:
read
r
<
     那么，解析命令行中的字符串就显得比较关键。如下函数cmdParser就是解析字符串函数。

void cmdParser(char *cmdLine)
{
      char cmd[100];
      int data = 0;
      if(strlen(cmdLine)<=0){showMSG("/n/r");return ;}   //如果命令为空
      sscanf(cmdLine,"%s %x",cmd,&data);     //将字符串解析成命令和数据。比如写命令+写数据
      strcpy(cmd,::strlwr(cmd));   //转小写

      if(strcmp(cmd,"start")==0||strcmp(cmd,"[")==0||strcmp(cmd,"s")==0)
      {
             IICStart();
             showMSG("IIC Bus start");  //显示工作状态
             clearCMD();                         //清除命令输入框内容，一般设置""即可
      }
      else if(strcmp(cmd,"stop")==0||strcmp(cmd,"]")==0||strcmp(cmd,"st")==0)
      {
             IICStop();
             showMSG("IIC Bus stop");
             clearCMD();

      }
      else if(strcmp(cmd,"write")==0||strcmp(cmd,"w")==0||strcmp(cmd,">")==0)
      {
             if(IICWriteByte(data))  //写data
             {
                    sprintf(cmd,"IIC write 0x%x",data);
                    showMSG(cmd);
             }
             else
             {
                    sprintf(cmd,"err: write 0x%x err",data);
                    showMSG(cmd);

             }
             clearCMD();
      }
      else if(strcmp(cmd,"read")==0||strcmp(cmd,"r")==0||strcmp(cmd,"<")==0)
      {
             data = IICReadByte();
             sprintf(cmd,"IIC read 0x%x",data);
             showMSG(cmd);
             clearCMD();
      }
      else if(strcmp(cmd,"ack")==0||strcmp(cmd,"a")==0)
      {
             IICSendAck(1);
             showMSG("Send ACK");
             clearCMD();
      }
      else if(strcmp(cmd,"noack")==0||strcmp(cmd,"na")==0)
      {
             IICSendAck(0);
             showMSG("Send NO ACK");
             clearCMD();
      }
      else
      {
              showMSG("err: unknown command");
              clearCMD();
      }
}

（2）利用基础之三的IIC的基础语句，组合成特定芯片的控制处理函数

void IICWriteSN3199OneCommand(BYTE subaddr,BYTE data)
{
      IICStart();
      IICWriteByte(SN3199_IIC_WRITE_ADDRESS);
      IICWriteByte(subaddr);
      IICWriteByte(data);
      IICStop();
}