IF Cmd_reg2 THEN --若"发送允许",则将Sh_reg7作为当前发送位
SDA_tmp = Sh_reg7;
ELSE
SDA_tmp = VCC;
END IF;
St.clk = SysClk;
St.ena = BaudGen;
CASE St IS --控制传输8位数据的状态机
WHEN t0 =