【iCore4 双核心板_FPGA】例程一：GPIO输出实验——点亮LED

实验现象：

三色LED循环点亮。

核心源代码：

module led_ctrl(
    input clk_25m,
    input rst_n,
    output fpga_ledr,
    output fpga_ledg,
    output fpga_ledb
);

//--------------------cnt----------------------------------//
reg [24:0]cnt;
reg [2:0]led_cnt;

always @ (posedge clk_25m or negedge rst_n)
if(!rst_n)
        begin
            cnt <= 25'd0;
            led_cnt <= 1'd0;
        end
else if(cnt == 25'd5000000)
        begin
            cnt <= 25'd0;
if(led_cnt == 3'd2)
                led_cnt <= 3'd0;
else 
                led_cnt <= led_cnt + 1'd1;
        end        
else
        begin
            cnt <= cnt + 1'd1;
        end

//--------------------led_ctrl----------------------------//
/*led状态切换状态机*/
reg ledr,ledg,ledb;

always @ (posedge clk_25m or negedge rst_n)
if(!rst_n)
        begin
            ledr <= 1'd1;
            ledg <= 1'd1;
            ledb <= 1'd1;
        end
else 
case(led_cnt)                        
3'd0:                                //红灯亮
                begin
                    ledr <= 1'd0;
                    ledg <= 1'd1;
                    ledb <= 1'd1;
                end
3'd1:                                //绿灯亮
                begin
                    ledr <= 1'd1;
                    ledg <= 1'd0;
                    ledb <= 1'd1;
                end
3'd2:                                //蓝灯亮
                begin
                    ledr <= 1'd1;
                    ledg <= 1'd1;
                    ledb <= 1'd0;
                end
default:                        //都不亮
                begin
                    ledr <= 1'd1;
                    ledg <= 1'd1;
                    ledb <= 1'd1;
                end
        endcase

assign {fpga_ledr,fpga_ledg,fpga_ledb}    = {ledr,ledg,ledb};    

//--------------------endmodule---------------------------//
endmodule

源代码下载链接：

链接：http://pan.baidu.com/s/1nu74Iy1 密码：dz3y

iCore4链接：