异步复位同步释放
参考
http://www.cnblogs.com/qiweiwang/archive/2010/11/25/1887888.html
http://blog.chinaaet.com/stephenkung/p/34054
异步复位同步释放代码
module rst(
input clk,
input rst_n,
output reg rst_out
);
reg rst_R;
always@(posedge clk, negedge rst_n)
begin
if(!rst_n)
begin
rst_R <= 1'b0;
rst_out <= 1'b0;
end
else
begin
rst_R <= 1'b1;
rst_out <= rst_r;
end
end
endmodule
综合出的电路: