**结果__**：light_s与light_w都是输出，但是这个三段式中，st_curr也即现态始终不能立即变为st_next，尝试过改阻塞非阻塞但没有任何用输出结果都一样。
**题目：__**一个红绿灯，s，w，小clk生成大CLk,经过一定的周期变换红绿灯
问题遇到的现象和发生背景
问题相关代码，请勿粘贴截图
/*红绿灯 两个灯，
对其中一个进行状态分析，经过一定的大CLK后转变状态*/
/*
未完善每个灯时间
current状态始终会差一个周期变为next状态（阻塞or非阻塞）
☹☹☹☹☹☹☹☹
*/
module maincode(
input clk,
input rst,
output [2:0]light_s,
output [2:0]light_w
);
parameter Green=0;
parameter Red=1;
parameter Red1=2;
parameter Yellow=3;
reg [2:0]light_s_temp;
reg [2:0]light_w_temp;
assign light_s=light_s_temp;
assign light_w=light_w_temp;
reg [2:0]st_curr=Green;
reg [2:0]st_next=Green;
reg CLK;
reg [32:0]counter;
always @(posedge clk) //1M=10^6
begin
if(counter<=2)
begin
CLK<=0;
counter+=1;
end
else if(counter<=4)
begin
CLK<=1;
counter+=1;
end
else
counter=0;
end
//第一段 时序逻辑
always @(posedge clk)//同步清零
begin
if(!rst)
st_curr=Green;
else
st_curr=st_next;
end
reg [15:0]counter1=0;
reg [15:0]counter2=0;
reg [15:0]counter3=0;
reg [15:0]counter4=0;
//第二段 组合逻辑
always @(posedge CLK)
begin
case(st_curr)
Green:
begin
if(counter1<19)
begin
counter1=counter1+1;
st_next<=Green;
end
else if(counter1==19)
begin
counter1=0;
st_next<=Yellow;
end
end
Yellow:
begin
if(counter2<3)
begin
counter2=counter2+1;
st_next<=Yellow;
end
else if(counter2==3)
begin
counter2=0;
st_next<=Red;
end
end
Red:
begin
if(counter3<57)
begin
counter3+=1;
st_next<=Red;
end
else if(counter3==57)
begin
counter3=0;
st_next<=Red1;
end
end
Red1:
begin
if(counter4<3)
begin
counter4+=1;
st_next<=Red1;
end
else if(counter4==3)
begin
counter4=0;
st_next<=Green;
end
end
endcase
end
//第三段 时序逻辑
//[2:0]========0 1代表G Y R的亮与灭
always @(posedge clk)
begin
if(st_curr==Green)
begin
light_s_temp<=3'b100;
light_w_temp<=3'b001;
end
else if(st_curr==Yellow)
begin
light_s_temp<=3'b010;
light_w_temp<=3'b001;
end
else if(st_curr==Red)
begin
light_s_temp<=3'b001;
light_w_temp<=3'b100;
end
else
begin
light_s_temp<=3'b001;
light_w_temp<=3'b010;
end
end
endmodule
