键盘扫描的VHDL实现

1、library ieee;use ieee.std_logic_1164.all;use ieee.std_logic_unsigned.all;entity jp isport(clk,start:in std_logic;kbcol:in std_logic_vector(3 downto 0);-行扫描信号kbrow:out std_logic_vector(3 downto 0);-列扫描信号seg7_out:out std_logic_vector(6 downto 0);- 显示控制信号 scan:out std_logic_vector(7 downto 0)-数码管地址选择控制

2、信号);end jp;architecture one of jp issignal count,sta:std_logic_vector(1 downto 0);signal seg7:std_logic_vector(6 downto 0);signal dat:std_logic_vector(4 downto 0);signal fn:std_logic;-按键标志位，判断是否有键被按下beginscan<="00000001"- 只使用一个数码管显示-循环扫描计数器process(clk)beginif clk'event and clk='

3、1'thencount<=count+1;end if;end process;-循环列扫描process(clk)beginif clk'event and clk='1'thencase count iswhen "00"=>kbrow<="0001"sta<="00"when "01"=>kbrow<="0010"sta<="01"when "10"=>kbrow<

4、="0100"sta<="10"when "11"=> kbrow<="1000" sta<="11"when others=> kbrow<="1111"end case;end if;end process;一行扫描译码process(clk,start)beginif start='O'thenseg7<="0000000"elsif clk'event and clk='rt

5、hencase sta iswhen "00"=>case kbcol iswhen "0001"=>seg7<="1111001" dat<="OOO11"when "0010"=>seg7<="1101101" dat<="00010"when "0100"=>seg7<="0110000" dat<="00001"when &quo

6、t;1000"=>seg7<="1111110" dat<="00000"when others=> seg7<="0000000" dat<="11111"end case;when "01"=>case kbcol iswhen "0001"=>seg7<="1111000" dat<="00111"when "0010"=>seg7&l

7、t;="1011111" dat<="00110"when "0100"=> seg7<="1011011"dat<="00101"when "1000"=>seg7<="0110011" dat<="00100"when others=> seg7<="0000000" dat<="11111"end case;when "1

8、0"=>case kbcol iswhen "0001"=>seg7<="0011111" dat<="01011"when "0010"=> seg7<="1110111" dat<="01010"when "0100"=>seg7<="1111011" dat<="01001"when "1000"=>seg7<

9、="11111H"； dat<="01000"when others=>seg7<="0000000" dat<="111H"end case;when "11"=>case kbcol iswhen "0001"=>seg7<="1000111" dat<="01111"when "0010"=>seg7<="1001111" dat&

10、lt;="01110"when "0100"=>seg7<="0111101" dat<="01101"when "1000"=>seg7<="1001110" dat<="01100"when others=> seg7<="0000000" dat<="11111"；end case;when others=>seg7<="0000000"end case;end if;end process;-产生按键标志位，用于存储按键信息fn<=not