有关4X4矩阵键盘FPGA的程序的分析，有谁帮我分析一下这个状态机的程序啊

是应该还有col的输出，这才是整个扫描程序的重点。如果扫描的原理懂了的话，程序好像也没这么难理解啊，简单讲一下，在NO_KEY_PRESSED，col输出0000，如果有按键按下，当前行的row连接到col，则按下的那一行电平为0，转到SCAN_COL0。行值由row可知，开始逐列扫描以确定列值；在SCAN_COL0状态，col输出1000，若是第一列的按键，则row应该变为1111，即可确定是第一列，否则转到第二列扫描，col输出0100···类推

library ieeeuse ieee.std_logic_1164.all

entity keyarray is port(

sysclk : in std_logic

key1 : in std_logic_vector(3 downto 0)

key2 : out std_logic_vector(3 downto 0)

duan : out std_logic_vector(7 downto 0)

wei : out std_logic

)

end keyarray

architecture rtl of keyarray issignal led: std_logic_vector(7 downto 0)

begin

process(sysclk)VARIABLE sig_com : std_logic_vector(3 downto 0) := "1110"

begin

if(sysclk 'event and sysclk='1')then

case sig_com is

WHEN "1110" =>

key2<=sig_com

if(key1/="1111")then

led<=sig_com &key1

sig_com:="1110"

else

sig_com:="1101"

end if

WHEN "1101" =>

key2<=sig_com

if(key1/="1111")then

led<=sig_com&key1

sig_com:="1101"

else

sig_com:="1011"

end if

WHEN "1011" =>

key2<=sig_com

if(key1/="1111")then

led<=sig_com&key1

sig_com:="1011"

else

sig_com:="0111"

end if

WHEN "0111" =>

key2<=sig_com

if(key1/="1111")then

led<=sig_com &key1

sig_com:="0111"

else

sig_com:="1110"

end if

when others =>sig_com:="1110"

end case

end if

end process

process(sysclk)begin

wei<='1'

case led is

when "01110111" =>duan <="11111000" --7

when "10110111" =>duan <="10000011" --b

when "11010111" =>duan <="10001110" --f

when "11100111" =>duan <="10110000" --3

when "01111110" =>duan <="10011001" --4

when "10111110" =>duan <="10000000" --8

when "11011110" =>duan <="11000110" --c

when "11101110" =>duan <="11000000" --0

when "01111101" =>duan <="10010010" --5

when "10111101" =>duan <="10010000" --9

when "11011101" =>duan <="10100001" --d

when "11101101" =>duan <="11111001" --1

when "01111011" =>duan <="10000010" --6

when "10111011" =>duan <="10001000" --a

when "11011011" =>duan <="10000110" --e

when "11101011" =>duan <="10100100" --2

when others=>duan <="11000000" --0

end case

end process

end rtl

假设按下的是S1键进行如下检测（4*4键盘）

先在P3口输出

p3 00001111

低四位 行会有变化

cord_h =00001111&00001110 =00001110

if !=00001111

延时0.1us

cord_h=00001110&00001111=00001110

if !=00001111

P3再输出11111110

P3=00001110|11110000=11111110

输出高四位

cord_l=P3&0xf0 //此时P3口就是输入值01111110 而不是上面的11111110

cord_l=01111110&11110000=01110000

cord_h+cord_l=00001110+01110000=01111110=0x7e //此编码即为S1的编码

#include <reg52.h>//包含头文件

#define uchar unsigned char

#define uint unsigned int

unsigned char const table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,

0x77,0x7c,0x39,0x5e,0x79,0x71}//0-F

uchar keyscan(void)

void delay(uint i)

void main()

{

uchar key

P2=0x00//1数码管亮 按相应的按键，会显示按键上的字符

while(1)

{

key=keyscan()//调用键盘扫描，

switch(key)

{

case 0x7e:P0=table[0]break//0 按下相应的键显示相对应的码值

case 0x7d:P0=table[1]break//1

case 0x7b:P0=table[2]break//2

case 0x77:P0=table[3]break//3

case 0xbe:P0=table[4]break//4

case 0xbd:P0=table[5]break//5

case 0xbb:P0=table[6]break//6

case 0xb7:P0=table[7]break//7

case 0xde:P0=table[8]break//8

case 0xdd:P0=table[9]break//9

case 0xdb:P0=table[10]break//a

case 0xd7:P0=table[11]break//b

case 0xee:P0=table[12]break//c

case 0xed:P0=table[13]break//d

case 0xeb:P0=table[14]break//e

case 0xe7:P0=table[15]break//f

}

}

}

uchar keyscan(void)//键盘扫描函数，使用行列反转扫描法

{

uchar cord_h,cord_l//行列值

P3=0x0f //行线输出全为0

cord_h=P3&0x0f//读入列线值

if(cord_h!=0x0f)//先检测有无按键按下

{

delay(100) //去抖

cord_h=P3&0x0f //读入列线值

if(cord_h!=0x0f)

{

P3=cord_h|0xf0 //输出当前列线值

cord_l=P3&0xf0 //读入行线值

return(cord_h+cord_l)//键盘最后组合码值

}

}return(0xff)//返回该值

}

void delay(uint i)//延时函数

{

while(i--)

}

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