一组排队函数，我以前开发的一个项目中用的。
上位机向下位机发送的命令用一个队列暂存起来，下位机从队列中逐一取出命令执行，直到命令执行完毕为止。
每一组命令均为3个字节，命令队列可容纳6组命令；
下位机向上位机发送的节点数据每组均为3个字节，命令队列可容纳6组数据；,Lined up a group function, I' ve developed a project using the. PC-bit machine down the order to send a temporary queue up, the next-bit machines removed from the queue in order to implement one by one, until the order until the implementation. Each group are three-byte command, the command queue can accommodate 6 Group orders　under-bit machine-bit machine to send up the node data in each group are three bytes, the command queue can accommodate 6 sets of data