适用于8位动态扫描的串行传输-锁存的低有效LED驱动电路，程序根据Disp_Buf[LED_Num]内信息逐位更新LED显示,基于ZLG easy1138学习板-For 8-bit dynamic scan of the serial transmission- Latch LED driver circuit of low-effective, procedures, according to Disp_Buf [LED_Num] update the information in bit-L