99到0减法计数器verilog数码管
时间: 2023-07-29 07:11:26 浏览: 54
以下是一个简单的Verilog代码,实现99到0的减法计数器,并将结果显示在数码管上:
```verilog
module subtract_counter(clk, reset, anodes, segments);
input clk, reset;
output reg [3:0] anodes;
output reg [7:0] segments;
reg [7:0] count;
always @(posedge clk or posedge reset) begin
if (reset) begin
count <= 8'h99;
end else begin
count <= count - 1;
end
end
always @(count) begin
case(count)
8'h00: segments <= 8'b11000000; // 0
8'h01: segments <= 8'b11111001; // 1
8'h02: segments <= 8'b10100100; // 2
8'h03: segments <= 8'b10110000; // 3
8'h04: segments <= 8'b10011001; // 4
8'h05: segments <= 8'b10010010; // 5
8'h06: segments <= 8'b10000010; // 6
8'h07: segments <= 8'b11111000; // 7
8'h08: segments <= 8'b10000000; // 8
8'h09: segments <= 8'b10010000; // 9
8'h0A: segments <= 8'b10001000; // A
8'h0B: segments <= 8'b10000011; // B
8'h0C: segments <= 8'b11000110; // C
8'h0D: segments <= 8'b10100001; // D
8'h0E: segments <= 8'b10000110; // E
8'h0F: segments <= 8'b10001110; // F
default: segments <= 8'b11111111; // no display
endcase
end
always @(anodes) begin
case(anodes)
4'b0001: anodes <= 4'b0010;
4'b0010: anodes <= 4'b0100;
4'b0100: anodes <= 4'b1000;
4'b1000: anodes <= 4'b0001;
default: anodes <= 4'b0001;
endcase
end
endmodule
```
这个代码使用一个名为`count`的8位寄存器,从8'h99开始减一,直到达到0。每当`count`改变时,一个`case`语句将根据当前值设置数码管的段选信号。`anodes`信号是用于选择哪个数码管(如果有多个)应该被显示。在这个代码中,我们假设只有一个数码管,并使用一个简单的循环来选择每个数码管。