VHDL秒表功能.docx

1、VHDL秒表功能本程序利用VHDL实现功能：按下键开始计时，再次按下停止计时，再次按下清零，再次按下开始计时4位数码管显示，最大99.99秒。程序分为分频模块，按键消抖模块/数码管显示转换模块和top模块-通用偶数分频器输入时钟和复位信号，输出分频后的时钟library ieee;use ieee.std_logic_1164.all;use ieee.std_logic_arith.all;use ieee.std_logic_unsigned.all;entity gen_div is generic(div_param:integer:=1);-分频因子,分频为2*div_param，默

2、认2分频 port ( clk:instd_logic;-输入时钟 bclk:outstd_logic;-分频输出 resetb:instd_logic-复位信号 );end gen_div;architecture behave of gen_div issignal tmp:std_logic;-输出暂存寄存器signal cnt:integer range 0 to div_param:=0;-计数寄存器begin- process(clk,resetb) begin if resetb=1 then -reset有效时,bclk始终是0 cnt=0; tmp=0; elsifrisin

3、g_edge(clk) then cnt=cnt+1; if cnt=div_param-1 then tmp=not tmp;-取反信号 cnt=0; end if; end if; end process; bclkclkin, resetb=not resetin, bclk=clk_1k );-check_key0_state: process(clk_1k,resetin,key) variable cnt:integer range 0 to 63:=0; begin if resetin=0 then key_out=0; sk_state_key0 if key=1 then-

4、=0位按下，1位松开 sk_state_key0=check_down; key_out=0;-松开了，输出0 elsif key=0 then-有键按下，准备消抖 sk_state_key0-延时10ms,消抖 cnt:=cnt+1; if cnt=10 then sk_state_key0 if key=1 then sk_state_key0=check_down;-重新检测 elsif key=0 then-确实有键按下 key_out= 1; -输出1 sk_state_key0null; end case; end if; end if; end process;end behav

5、e;数码管显示转换模块输入时钟复位信号和数字，输出段码-把输入的整型转变为对应显示段码library ieee;use ieee.std_logic_1164.all;use ieee.std_logic_arith.all;use ieee.std_logic_unsigned.all;entity led_change is port ( clkin,resetin:instd_logic;-时钟，复位信号输入 data_in:in integer range 0 to 21;-输入整型 data_out:outstd_logic_vector(7 downto 0)-数码管段码输出 );

6、end led_change;architecture behave of led_change isbegin process(clkin,resetin,data_in) begin if resetin=1 then data_outdata_outdata_outdata_outdata_outdata_outdata_outdata_outdata_outdata_outdata_outdata_outdata_outdata_outdata_outdata_outdata_outdata_outdata_outdata_outdata_outdata_outclk_init, re

7、setb= not reset_init, bclk=clk_sm );gen_data_1:-个位段码转换 led_change port map ( clkin=clk_init, resetin=not reset_init, data_in=data_1_tmp, data_out=data_1 );gen_data_10:-十位段码转换 led_change port map ( clkin=clk_init, resetin=not reset_init, data_in=data_10_tmp, data_out=data_10 );gen_data_100:-百位段码转换 le

8、d_change port map ( clkin=clk_init, resetin=not reset_init, data_in=data_100_tmp, data_out=data_100 );gen_data_1000:-千位段码转换 led_change port map ( clkin=clk_init, resetin=not reset_init, data_in=data_1000_tmp, data_out=data_1000 );key_sig:-调用按键消抖程序 sig_key port map ( clk_init,reset_init,sw,key_out_in

9、it ); gen_cnt_50k:-cnt_50k循环计数,四个状态的循环周期是20us*4=80us，即为扫描周期 process(clk_sm,reset_init,data_1000,data_100,data_10,data_1) begin if reset_init=0 then cnt_50k=00; else if rising_edge(clk_sm) then cnt_50k com=0111;data com=1011;data com=1101;data com=1110;data com if key_out_init=0 then 松开，置1 key_flog:=

10、1; end if; if key_out_init=1 and key_flog=1 then按下，且之前是松开转到状态2开始计时，按下后flog置0 sw_state if key_out_init=0 then-松开健开始计时，且置1 key_flog:=1; cnt_clk_1k:=cnt_clk_1k+1; data_1_tmp = ( cnt_clk_1k /50 / 10 ) rem 10; data_10_tmp = ( cnt_clk_1k /50 / 100 ) rem 10; data_100_tmp = ( cnt_clk_1k /50 / 1000 ) rem 10+

11、10; data_1000_tmp = ( cnt_clk_1k /50 / 10000 ) rem 10; end if; if key_flog=1 then 置1表示已经松开 if key_out_init=1 then 再次按下 sw_state if key_out_init=0 then key_flog:=1; end if; if key_flog=1 then if key_out_init=1 then sw_state= sw_1; key_flog:=0; cnt_clk_1k:=0; data_1_tmp =0;-清零 data_10_tmp =0; data_100_tmp =0; data_1000_tmp sw_state= sw_1; end case; end if;end process; end behave;-top程序应该有复位信号，本除没有加。可在上面进程里面加，按下后说有变量清零。以上程序已经验证。