waterlily

我曾用vhdl实现过简单的pwm.
if speedin="1100100" then
speedin<=(others=>'0');
else
speedin<=speedin+'1';
end if;
---------------
if motor_flag="01" then
IN2_s <= '0';
if speedin IN1_s <= '1';
else
IN1_s <= '0';
end if;

end if;

自己随机设置running_speed的值产生不同占空比的IN1_s信号（pwm信号）