VHDL键盘扫描

1、一、设计目的稳固和运用所学课程，理论联系实际，提高分析、解决计算机技术实际问题的独立工作能力，通过对FPGA几个简单的模块设计，进一步加深对计算机原理以及数字电路应用技术方面的了解与认识，进一步熟悉数字电路系统设计、制作与调试的方法和步骤。二、设计内容1设计一个4×4的键盘扫描模块，要求有防抖动功能。2用键盘控制16×16点阵LED显示各种字符。3用键盘控制蜂鸣器发声，能有各种音调。三、实现方法本系统的系统组成及连接原理如图3.1所示，主系统由四个功能模块组成：分频模块为键盘扫描模块和提供时钟、键盘扫描模块、LED点阵模块、发声模块。LED点阵发声模块键盘扫描模块分频模块时

2、钟输入接蜂鸣器接LED点阵接键盘图3.1整体模块划分1、分频模块分频模块的作用是把2MHZ的时钟分成1kHZ和500HZ，为键盘扫描模块和LED点阵模块提供时钟。主要方法是通过计数器实现分频。分频模块如图3.2，clk是输入时钟，clkout_kb是输入给键盘扫描模块使用，clkout_LED是输入给LED点阵模块使用。图3.2 分频模块视图其仿真结果如图3.3图 3.3分频模块仿真2、键盘扫描模块2.1行列式键盘原理行列式键盘又叫做矩阵式键盘。用带有I/O口的线组成行列结构，按键设置在行列的交点上。本次试验用到的是4×4的行列结构键盘，可以构成16个按键。这样，当按键数量平方增长是

3、，I/O口只是线性增长，这样就可以节省I/O口。行列式键盘的原理如图3.4所示。CDEF89AB45670123keyin上拉电阻keydrv图 3.4 行列式键盘的原理按键设置在行列线交叉点，行、列线分别连接到按键开关的两端。列线通过上拉电阻接+5V的电压，即列线的输出被嵌位在高电平状态。判断按键中有无键按下时通过行线输入扫描信号，然后从列线读取到状态实现的。其方法是依次给行线送低电平，检查列线的输入。如果列线信号全为高电平，那么代表低电平所在的行中无按键按下；如果列线有输入为低电平，那么低电平信号所在的行和出现低电平的列的交点处有按键按下。设行扫描信号为keydrv3keydrv0，列线按

4、键输入信号keyin3keyin0与按键位置的关系如表3.1所示表3.1行扫描信号、列线按键输入信号与按键位置的关系keydrv3keydrv0keyin3keyin0对应的按键111011100110111011201113110111104110151011601117101111108110191011A0111B01111110C1101D1011E0111F2.2键盘扫描系统模块划分4×4键盘键盘译码电路扫描电路按键去抖动电路时钟输入输入键盘值图3.5 键盘扫描系统模块划分键盘扫描电路时用于产生keydrv3-keydrv0信号，其变化顺序为1110110110110111

5、周而复始的扫描。其停留在每个状态的时间大约有10ms。扫描电路的模型如下：图3.6 扫描电路外观接口扫描电路的仿真如图3.7所示：图3.7 扫描电路仿真键盘译码电路是从keydrv3keydrv0和keyin3keyin0译出按键值的电路，它的真值表如表1所示。键盘译码电路的模型如图3.8所示：图3.8 键盘译码电路外观其中键值keycode用5位编码，keycode为0000001111表示键值0F，keycode为11111时表示无按键按下。译码电路的仿真如图3.9所示：图3.9译码电路仿真图3.9仿真的是扫描信号在keydrv=1011时有按键按下，并且keyin=0111时的键值，由表

6、1可知这时的键值因该是B，而由图中可以看出仿真结果是5h0B，即预测结果与仿真结果一致。2.3 按键去抖动电路实现由于机械触点的弹性作用,触点在闭合和断开瞬间的电接触情况不稳定,造成了电压信号的抖动现象,如图3.10所示。键的抖动时间一般为 510ms。这种现象会引起FPGA对于一次键操作进行屡次处理，因此须设法消除键接通或断时的抖动现象。去抖动的方法有硬件和软件两种：硬件去抖动和软件去抖动。图3.10按键抖动现象去抖动模块采用屡次连续检测输入键值的原理防抖。当检测到有键值输入时并不马上输出，而是当16次输入的键值都一样时才输出，其中只要有一次键值不同的话计数器都会置零，重新记数。这样就能消除

7、按键的抖动影响。其模块外观如图3.11所示。图3.11去抖动模块外观按键去抖动仿真：图3.12按键去抖动仿真由仿真图形可以看出，输入keyvaluein开始和结束时都产生抖动，但经过去抖模块后抖动消失了。起到了去抖动的功能。3、16×16 LED 点阵显示屏的设计3.1 16x16 LED点阵的工作原理及连接组成方式：16x16 LED点阵的工作原理同8x8 LED点阵的工作原理，图3.13是8x8的LED点阵单色行共阳模块的内部结构图，其单点工作电压Uf为18 V，正向电流IF为810 mA。当某一行线为高电平而某一列线为低时，其行列交叉的点就被点亮；而当其某一列线为高时，其行列交

8、叉的点为暗；当某一行线为低电平时，无论列线如何，对应这一行的点全部为暗。图3.13：8x8的LED点阵单色行共阳模块的内部结构图本实验采用的16x16 LED点阵用四个8x8点阵显示构成，其连接方法如图3.14所示。图中，将(A)和(B)的8列、(C)和(D)的8列分别对应相连，同时将(A)和(C)的8行、 (B)和(D)的8行分别对应相连。即可形成一个16行(每一行有16个LED)、16列(每一列也有16个LED)的16x16点阵显示器，可将这256个点称为一页，这样，显示字符时。只要对一页中对应的亮灭进行控制即可。图3.14：四个8x8点阵显示构成的16x16 LED点阵3.2 16x16

9、 LED点阵的驱动方式本实验采用动态扫描型驱动方式显示，即显示屏上的16行发光二极管共用一组列驱动存放器，然后通过行驱动管的分时工作，来使每行LED的点亮时间占总时间的116。只要每行的刷新速率大于50 Hz，利用人眼的视觉暂留效应，人们就可以看到一幅完整的文字或画面。扫描驱动分行扫描驱动和列扫描驱动。由于16x16点阵显示器有16行，故使用行扫描信号，本电路中参加了一个4-16线译码器，其输入是一个频率为1000Hz的时钟信号，内部采用4位二进制加法器，分别为00001111，然后使每种状态只控制一路输出，解码输出为低态扫描信号，即会有16路输出。本实验的列信号由事先存于存放器中的16进制码

10、构成，每个矩阵表示一个字符的列扫描信号，伴随行扫描信号进行交替的扫描，其设计图见附录中16x16 LED点阵扫描设计草图。本实验所显示的字符由键盘编码所确定，其编码与显示字符对应的关系如表3.2所示：表3.2：键盘编码与对应显示字符键盘编码00000000010001000011显示字符0123键盘编码00100001010011000111显示字符4567键盘编码01000010010101001011显示字符89AB键盘编码01100011010111001111显示字符CDEF键盘编码11111显示字符音符图形3.3 16x16 LED点阵驱动电路16x16 LED点阵驱动外观电路如图3

11、.15所示：图3.15 16x16 LED点阵驱动电路外观16x16 LED点阵驱动电路原理图如图3.16所示：图3.16：16x16 LED点阵驱动电路原理图驱动行信号仿真如图3.17所示：图3.17驱动行信号4、发声模块4.1音调的产生音调的产生是通过分频实现的。设计要求产生不同的音调，就需要不同的分频器。可以先构造一个分频器，然后通过VHDL中的参数传递语句构造出十二个不同的分频器，其分频数见表3.2输入时钟是2MHz。表3.3音符频率对照表键值音符频率分频数键值音符频率分频数0低53925102.04087中57842551.02041低64404545.45458中68802272.

12、72732低74944048.5839中79882024.29153中15233824.0918A高110461912.04594中25783460.2076B高211751702.12775中36593034.9014C高313181517.45076中46982865.3295D高413971431.63924.2电路实现发声模块其内部是一个有一个输入，十二个输出的分频器，用于产生十二种音调。然后根据键值判断哪个口输出。其顶层视图如图3.18所示。图3.18发声模块外观发声模块的仿真见图3.19图3.19发声模块仿真仿真波形中l5h4是分频器的十二个输出口，当键值是C时speaker输入的

13、是h3的值，到达了要求。5、顶层模块实现顶层电路只是把分频模块、键盘扫描模块、LED点阵模块和发声模块连接起来，其外观和内部结构如图3.20和3.21所示。图3.20顶层模块外观图3.21顶层模块内部结构6、管脚的定义管脚的定义如表3.4所示表3.4 管脚的定义I/O NameI/O DirectionLocBankclkInputP3BANK7SpeakerOutputP95BANK4keydrv<0>OutputP120BANK3keydrv<1>OutputP121BANK3keydrv<2>OutputP122BANK3keydrv<3>

14、OutputP123BANK3keyin<0>InputP125BANK3keyin<1>InputP127BANK3keyin<2>InputP129BANK3keyin<3>InputP132BANK2LEDcolumn<0>OutputP133BANK2LEDcolumn<1>OutputP134BANK2LEDcolumn<2>OutputP136BANK2LEDcolumn<3>OutputP138BANK2LEDcolumn<4>OutputP139BANK2LEDcolum

15、n<5>OutputP140BANK2LEDcolumn<6>OutputP141BANK2LEDcolumn<7>OutputP147BANK2LEDcolumn<8>OutputP148BANK2LEDcolumn<9>OutputP149BANK2LEDcolumn<10>OutputP150BANK2LEDcolumn<11>OutputP151BANK2LEDcolumn<12>OutputP152BANK2LEDcolumn<13>OutputP162BANK1LEDcolu

16、mn<14>OutputP163BANK1LEDcolumn<15>OutputP164BANK1LEDrow<0>OutputP165BANK1LEDrow<1>OutputP167BANK1LEDrow<2>OutputP73BANK5LEDrow<3>OutputP74BANK5LEDrow<4>OutputP70BANK5LEDrow<5>OutputP71BANK5LEDrow<6>OutputP68BANK5LEDrow<7>OutputP69BANK5LEDro

17、w<8>OutputP63BANK5LEDrow<9>OutputP67BANK5LEDrow<10>OutputP61BANK5LEDrow<11>OutputP62BANK5LEDrow<12>OutputP59BANK5LEDrow<13>OutputP60BANK5LEDrow<14>OutputP57BANK5LEDrow<15>OutputP58BANK5附录 程序代码1、顶层模块library IEEE;use IEEE.STD_LOGIC_1164.ALL;use IEEE.STD_

18、LOGIC_ARITH.ALL;use IEEE.STD_LOGIC_UNSIGNED.ALL;- Uncomment the following library declaration if instantiating- any Xilinx primitives in this code.-library UNISIM;-use UNISIM.VComponents.all;entity play_show is Port ( clk : in STD_LOGIC; keyin : in STD_LOGIC_VECTOR (3 downto 0); keydrv : out STD_LOG

19、IC_VECTOR (3 downto 0);LEDrow : out STD_LOGIC_VECTOR(15 downto 0);-LED行扫描信号 LEDcolumn : out STD_LOGIC_VECTOR(15 downto 0); Displayshow: out STD_LOGIC_VECTOR (6 downto 0); Displayselect: out STD_LOGIC_VECTOR (3 downto 0); speaker : out STD_LOGIC);end play_show;architecture rtl of play_show iscomponen

20、t freq_divisionPort ( clk:in STD_LOGIC; clkout_kb:out STD_LOGIC; clkout_LED:out STD_LOGIC; clkout_display:out std_logic);end component;component keyboardPort ( clk : in STD_LOGIC;-扫描时钟，周期10ms keyin : in STD_LOGIC_VECTOR (3 downto 0); keydrv : out STD_LOGIC_VECTOR(3 downto 0); keyvalue : out STD_LOGI

21、C_VECTOR(4 downto 0);-输出扫描信号end component;component LEDArrayPort ( clk : in STD_LOGIC;-时钟信号,经分灯鞯玫1ms脉冲 keycode : in STD_LOGIC_VECTOR(4 downto 0);-键盘给的编码 LEDrow : out STD_LOGIC_VECTOR(15 downto 0);-LED行扫描信号 LEDcolumn : out STD_LOGIC_VECTOR(15 downto 0)-LED列信号 );end component;component playport (clk:i

22、n STD_LOGIC;keyvalue:in STD_LOGIC_VECTOR(4 downto 0);speaker:out STD_LOGIC);end component;component IBUF port (I: in std_logic; O: out std_logic); end component;component Display Port ( Keyvalue : in STD_LOGIC_VECTOR (4 downto 0); clk: in STD_LOGIC; Display : out STD_LOGIC_VECTOR (6 downto 0); Disel

23、ect : out STD_LOGIC_VECTOR (3 downto 0);end component;-signal clkin:STD_LOGIC;signal clkout_kb,clkout_LED,clkout_display:STD_LOGIC;-signal keydrv1:STD_LOGIC_VECTOR (3 downto 0);signal keyvalue1:STD_LOGIC_VECTOR (4 downto 0);signal CLK_SIG: std_logic;begin-keydrv<=keydrv1;U1: IBUF port map (I =>

24、; clk, O => CLK_SIG);U2freq_division:freq_divisionport map(CLK_SIG,clkout_kb,clkout_LED,clkout_display);U3keyboard:keyboardport map(clkout_kb,keyin,keydrv,keyvalue1);U4LEDArray1616:LEDArrayport map(clkout_LED,keyvalue1,LEDrow,LEDcolumn);U5Uplay:playport map(CLK_SIG,keyvalue1,speaker);U6Display:Di

25、splayport map(keyvalue1,clkout_display,Displayshow,Displayselect);end rtl;2、分频器entity fredivn isgeneric(N:integer:=2); Port ( clkin:in STD_LOGIC; clkout:out STD_LOGIC);end fredivn;architecture Behavioral of fredivn issignal clk1:std_logic:='0'signal counter:integer range 0 to n;beginprocess(

26、clkin)begin if rising_edge(clkin)then if counter=(n-1)/2 then clk1<=not clk1; counter<=0; else counter<=counter+1; end if; end if; end process;clkout<=clk1;end Behavioral;3、总分频器entity freq_division isPort ( clk:in STD_LOGIC; clkout_kb:out STD_LOGIC; clkout_LED:out STD_LOGIC; clkout_displ

27、ay:out STD_LOGIC);end freq_division;architecture RTL of freq_division iscomponent fredivn isgeneric(N:positive); Port ( clkin:in STD_LOGIC; clkout:out STD_LOGIC);end component;beginU1:fredivngeneric map(N=>kb_N)port map(clk,clkout_kb);U2:fredivngeneric map(N=>LED_N)port map(clk,clkout_LED);U3:

28、fredivngeneric map(N=>display_N)port map(clk,clkout_display);end RTL;4、键盘扫描驱动entity keyscan is Port ( clkin : in STD_LOGIC;-扫描时钟，周期20ms keydrv : out STD_LOGIC_VECTOR(3 downto 0);-输出扫描信号end keyscan;architecture behavioral of keyscan issignal count : std_logic_vector(1 downto 0):="00"-计数器

29、信号beginprocess(clkin)beginif rising_edge(clkin) thenif count="11" thencount<="00"elsecount<=count+1;end if;end if;end process;process(count)begincase count iswhen "00"=>keydrv<="1110"when "01"=>keydrv<="1101"when "10&

30、quot;=>keydrv<="1011"when "11"=>keydrv<="0111"when others =>keydrv<="0000"end case;end process;end behavioral;5、键盘编码entity keydecoder is Port ( clkin: in std_logic; keyin : in STD_LOGIC_VECTOR (3 downto 0); keydrv : in STD_LOGIC_VECTOR (3 dow

31、nto 0); keycode : out STD_LOGIC_VECTOR (4 downto 0); end keydecoder;architecture Rtl of keydecoder issignal temp:STD_LOGIC_VECTOR (7 downto 0);signal keyvalue1:STD_LOGIC_VECTOR (4 downto 0):="11111"signal count:std_logic_vector(1 downto 0):="00"-signal keypressed:boolean:=false;-

32、signal q1,q2,q3,q4:boolean;begintemp<=keydrv&keyin;process(clkin)beginif falling_edge(clkin) thenif keyin="1111" thenif count="11" thenkeyvalue1<="11111"count<="00"elsecount<=count+1;end if;elsecount<="00"case temp iswhen"1110

33、1110"=>keyvalue1<="00000"when"11101101"=>keyvalue1<="00001"when"11101011"=>keyvalue1<="00010"when"11100111"=>keyvalue1<="00011"when"11011110"=>keyvalue1<="00100"when"1101

34、1101"=>keyvalue1<="00101"when"11011011"=>keyvalue1<="00110"when"11010111"=>keyvalue1<="00111"when"10111110"=>keyvalue1<="01000"when"10111101"=>keyvalue1<="01001"when"1011

35、1011"=>keyvalue1<="01010"when"10110111"=>keyvalue1<="01011"when"01111110"=>keyvalue1<="01100"when"01111101"=>keyvalue1<="01101"when"01111011"=>keyvalue1<="01110"when"0111

36、0111"=>keyvalue1<="01111"when others =>keyvalue1<=keyvalue1;end case;end if;end if;end process;keycode<=keyvalue1;end rtl;6、键盘防抖entity Antiwitter is Port ( clkin : in STD_LOGIC; keyvaluein : in STD_LOGIC_VECTOR (4 downto 0); keyvalueout : out STD_LOGIC_VECTOR (4 downto

37、0);end Antiwitter;architecture Behavioral of Antiwitter issignal TempNum:std_logic_vector(4 downto 0);signal Counter:std_logic_vector(4 downto 0);signal Start:std_logic;beginprocess(clkin)beginif rising_edge(clkin) then if Start='0' thenTempNum<="11111"keyvalueout<="1111

38、1"Start<='1'elseif keyvaluein/=TempNum thenTempNum<=Keyvaluein;Counter<="00000"elseif Counter="11111" thenkeyvalueout<=keyvaluein;Counter<="00000"elseCounter<=Counter+1;end if;end if;end if;end if;end process;end Behavioral;7、键盘顶层entity ke

39、yboard isPort ( clk : in STD_LOGIC;-扫描时钟，周期10ms keyin : in STD_LOGIC_VECTOR (3 downto 0); keydrv : out STD_LOGIC_VECTOR(3 downto 0); keyvalue : out STD_LOGIC_VECTOR(4 downto 0);-输出扫描信号end keyboard;architecture RTL of keyboard iscomponent keyscanPort ( clkin : in STD_LOGIC;-扫描时钟，周期10ms keydrv : out S

40、TD_LOGIC_VECTOR(3 downto 0);-输出扫描信号end component;component keydecoderPort ( clkin:in std_logic; keyin : in STD_LOGIC_VECTOR (3 downto 0); keydrv : in STD_LOGIC_VECTOR (3 downto 0); keycode : out STD_LOGIC_VECTOR (4 downto 0);end component;component Antiwitter Port ( clkin : in STD_LOGIC; keyvaluein

41、: in STD_LOGIC_VECTOR (4 downto 0); keyvalueout : out STD_LOGIC_VECTOR (4 downto 0);end component;signal keydrv1:STD_LOGIC_VECTOR (3 downto 0);signal key:std_logic_vector(4 downto 0);beginU1:keyscanport map(clk,keydrv1);U2:keydecoderport map(clk,keyin,keydrv1,key);U3:Antiwitterport map(clk,key,keyva

42、lue);keydrv<=keydrv1;end RTL;8、LED扫描entity LEDArray is Port ( clk : in STD_LOGIC;-时钟信号,经分频器得到1ms脉冲 keycode : in STD_LOGIC_VECTOR(4 downto 0);-键盘给的编码 LEDrow : out STD_LOGIC_VECTOR(15 downto 0);-LED行扫描信号 LEDcolumn : out STD_LOGIC_VECTOR(15 downto 0)-LED列信号 );end LEDArray;architecture Scan of LEDArr

43、ay issignal count : std_logic_vector(3 downto 0):="0000"-计数器信号begin-时钟信号触发的计数器计数-process(clk)beginif rising_edge(clk) thenif count="1111" thencount<="0000"elsecount<=count+1;end if;end if;end process;-由count信号引发的行列扫描-process(count)begin-列信号-case count iswhen "

44、;0000"=>LEDrow<=x"8000"when "0001"=>LEDrow<=x"4000"when "0010"=>LEDrow<=x"2000"when "0011"=>LEDrow<=x"1000"when "0100"=>LEDrow<=x"0800"when "0101"=>LEDrow<=x&q

45、uot;0400"when "0110"=>LEDrow<=x"0200"when "0111"=>LEDrow<=x"0100"when "1000"=>LEDrow<=x"0080"when "1001"=>LEDrow<=x"0040"when "1010"=>LEDrow<=x"0020"when "1011&

46、quot;=>LEDrow<=x"0010"when "1100"=>LEDrow<=x"0008"when "1101"=>LEDrow<=x"0004"when "1110"=>LEDrow<=x"0002"when "1111"=>LEDrow<=x"0001"when others=>LEDrow<=x"0000"en

47、d case;-行信号-case keycode is-显示0-when "00000"=>case count iswhen "0000"=>LEDcolumn<=x"03C0"when "0001"=>LEDcolumn<=x"07E0"when "0010"=>LEDcolumn<=x"0E70"when "0011"=>LEDcolumn<=x"0C30"

48、when "0100"=>LEDcolumn<=x"0C30"when "0101"=>LEDcolumn<=x"0C30"when "0110"=>LEDcolumn<=x"0C30"when "0111"=>LEDcolumn<=x"0C30"when "1000"=>LEDcolumn<=x"0C30"when "1001

49、"=>LEDcolumn<=x"0C30"when "1010"=>LEDcolumn<=x"0C30"when "1011"=>LEDcolumn<=x"0C30"when "1100"=>LEDcolumn<=x"0C30"when "1101"=>LEDcolumn<=x"0E70"when "1110"=>LEDc

50、olumn<=x"07E0"when "1111"=>LEDcolumn<=x"03C0"when others=>LEDcolumn<=x"0000"end case;-显示1-when "00001" =>case count iswhen "0000"=>LEDcolumn<=x"0080"when "0001"=>LEDcolumn<=x"0180"

51、when "0010"=>LEDcolumn<=x"0780"when "0011"=>LEDcolumn<=x"0F80"when "0100"=>LEDcolumn<=x"0180"when "0101"=>LEDcolumn<=x"0180"when "0110"=>LEDcolumn<=x"0180"when "0111

52、"=>LEDcolumn<=x"0180"when "1000"=>LEDcolumn<=x"0180"when "1001"=>LEDcolumn<=x"0180"when "1010"=>LEDcolumn<=x"0180"when "1011"=>LEDcolumn<=x"0180"when "1100"=>LEDc

53、olumn<=x"0180"when "1101"=>LEDcolumn<=x"0180"when "1110"=>LEDcolumn<=x"0FF0"when "1111"=>LEDcolumn<=x"0FF0"when others=>LEDcolumn<=x"0000"end case;-显示2-when "00010"=>case count isw

54、hen "0000"=>LEDcolumn<=x"03C0"when "0001"=>LEDcolumn<=x"07E0"when "0010"=>LEDcolumn<=x"0E70"when "0011"=>LEDcolumn<=x"0C30"when "0100"=>LEDcolumn<=x"0C30"when "0101&

55、quot;=>LEDcolumn<=x"0C30"when "0110"=>LEDcolumn<=x"0070"when "0111"=>LEDcolumn<=x"00E0"when "1000"=>LEDcolumn<=x"01C0"when "1001"=>LEDcolumn<=x"0380"when "1010"=>LEDco

56、lumn<=x"0700"when "1011"=>LEDcolumn<=x"0E00"when "1100"=>LEDcolumn<=x"0C00"when "1101"=>LEDcolumn<=x"0C00"when "1110"=>LEDcolumn<=x"0FF0"when "1111"=>LEDcolumn<=x"

57、;0FF0"when others=>LEDcolumn<=x"0000"end case;-显示3-when "00011"=>case count iswhen "0000"=>LEDcolumn<=x"03C0"when "0001"=>LEDcolumn<=x"07E0"when "0010"=>LEDcolumn<=x"0E70"when "0011&q

58、uot;=>LEDcolumn<=x"0C30"when "0100"=>LEDcolumn<=x"0C30"when "0101"=>LEDcolumn<=x"0C70"when "0110"=>LEDcolumn<=x"00E0"when "0111"=>LEDcolumn<=x"01C0"when "1000"=>LEDcol

59、umn<=x"00E0"when "1001"=>LEDcolumn<=x"0070"when "1010"=>LEDcolumn<=x"0030"when "1011"=>LEDcolumn<=x"0C30"when "1100"=>LEDcolumn<=x"0C30"when "1101"=>LEDcolumn<=x"0E70"when "1110"=>LEDcolumn<=x"07E0"when "1111"=>LEDcolumn<=x"03C0"when others=>LEDcolumn<=x"0000&q