题解 | #可置位计数器#
可置位计数器
https://www.nowcoder.com/practice/b96def986e29475e8100c213178b73a8
需要寄存器延迟一个周期输出才能符合所给时序
`timescale 1ns/1ns
module count_module(
input clk,
input rst_n,
input set,
input [3:0] set_num,
output reg [3:0]number,
output reg zero
);
reg [3:0]number_reg;//输出寄存器,延迟一拍才能通过题目所给时序
parameter MAX = 4'd15;
always @(posedge clk or negedge rst_n)begin
if(!rst_n)begin//复位
number_reg <= 4'd0;
number <= 4'd0;
zero <= 1'b0;
end
else if(set)begin//置位有效
number_reg <= set_num;
number <= number_reg;
end
else if(number_reg == MAX)begin//计数达最大值
number_reg <= 4'd0;
number <= number_reg;
end
else begin
if(number_reg == 4'd0)begin
zero <= 1'b1;
end
else begin
zero <= 1'b0;
end
number_reg <= number_reg + 1'b1;
number <= number_reg;
end
end
endmodule
