GW1NSR-LV4CQN48GC6/I5 FPGA呼吸灯

阿里云国内75折回扣微信号：monov8

阿里云国际，腾讯云国际，低至75折。AWS 93折免费开户实名账号代冲值优惠多多微信号：monov8 飞机：@monov6

环境

pwm.v

$ cat pwm.v
module Pwm(
input clk,
input [31:0] period,
input [31:0] duty,
output pwmout
);
reg [31:0] counter;
reg r_pwmout;
always @(posedge clk) begin

if(counter < duty) begin
r_pwmout = 1;
end
else begin
r_pwmout = 0;
end

case(counter)
default:
counter = counter + 1;
period:
counter = 0;
endcase

end

assign pwmout = r_pwmout;

top.v

$ cat top.v
module top(
input sys_clk,
input key1,
output led
);
parameter TIME_1MS = 1000;

reg [31:0] duty;

parameter pwm_period = 200 * TIME_1MS;
Pwm pwm(sys_clk, pwm_period, duty, led);

reg [31:0] counter;
reg [31:0] duty_step;
reg modify_duty;
reg duty_dir;
always @(posedge sys_clk) begin

counter = counter + 1;

case(counter % (TIME_1MS / 5))
0:
modify_duty = 1;
endcase

case(duty)
0:
duty_dir = 1;
pwm_period:
duty_dir = 0;
endcase

case(duty)
0 - pwm_period / 2:
duty_step = 10;
default:
duty_step = 2;
endcase

if(modify_duty) begin

if(duty_dir) begin
duty = duty + duty_step;
end
else begin
duty = duty - duty_step;
end
modify_duty = 0;

end

end