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

2、制信号);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 clkevent and clk=1thencountkbrow=0001;s

3、takbrow=0010;stakbrow=0100;stakbrow=1000;stakbrow=1111;end case;end if;end process;-行扫描译码process(clk,start)beginif start=0thenseg7case kbcol iswhen 0001=seg7=1111001;datseg7=1101101;datseg7=0110000;datseg7=1111110;datseg7=0000000;datcase kbcol iswhen 0001=seg7=1111000;datseg7=1011111;datseg7=1011011

4、;datseg7=0110011;datseg7=0000000;datcase kbcol iswhen 0001=seg7=0011111;datseg7=1110111;datseg7=1111011;datseg7=1111111;datseg7=0000000;datcase kbcol iswhen 0001=seg7=1000111;datseg7=1001111;datseg7=0111101;datseg7=1001110;datseg7=0000000;datseg7=0000000;end case;end if;end process;-产生按键标志位，用于存储按键信息fn=not (dat(0) and dat(1) and dat(2) and dat(3) and dat(4);process(fn)beginif fne