呼吸机(PWM波)原理图
代码如下
` time scale1ns/1 psmodulebreath _ led (inputsys _ clk,input sys_rst_n,output led ); reg [15:0] period_cnt; //周期计数频率1khz周期为1ms,因此计数值为1 ms/20 ns=50000 reg [ 15:0 ] duty _ cycle; //占空比计数值reg inc_dec_flag; //状态标志,递增为0,1 always @ (posedge sys _ clkornegedgesys _ rst _ n ) begin if (! sys_rst_n(Period_CNT=16'B0; elseif(period_CNT==16'd50000 ) period_cnt=16'b0; else period_cnt=period_cnt 1'b1; end always @ (posedge sys _ clkornegedgesys _ rst _ n ) begin if (! sys_rst_n(beginduty_cycle=16