假如按键返回的值为0xce,可知是pb0被拉低了，由此可判断是S1或者S2按下了，其他的同理。

当然只让P1=0xcf,是不能判断出具体的按键是哪个的，此时，如果我们取反既P1=0x30;

当按键返回值为0x10时，我们可得知01 0000，pb5=0，s1或者s2被按下，这个时候我们将0xce|0x10=0xde,就是唯一的值了。以此类推，得出其他的值来。

在stm32中是同样的大道理；

uint8_t KeyScan(void)

{

uint8_t HangValue = 0;

uint8_t LieValue = 0;

uint16_t KeyValue = 0;

uint8_t Tmp =0;

static uint8_t KeyConter = 0;

GPIO_SetBits(Colum1.port, (Colum1.pin|Colum2.pin|Colum3.pin|Colum4.pin));

GPIO_ResetBits(Line1.port,(Line1.pin|Line2.pin));

Tmp = GPIO_ReadInputData(Line1.port);

if ((Tmp&0x0F) != 0x0F)

{

if (KeyConter < 1)

{//去抖

KeyConter++;

}

else

{

HangValue = Tmp&0x0f;

GPIO_ResetBits(Colum1.port, (Colum1.pin|Colum2.pin|Colum3.pin|Colum4.pin));

GPIO_SetBits(Line1.port,(Line1.pin|Line2.pin));

Tmp = GPIO_ReadInputData(Colum1.port);

LieValue = Tmp&0x30;

KeyValue = (HangValue)|LieValue;

if (KeyValue)// KeyValue^KeyValueBkp

{

KeyValueBkp = KeyValue;

switch (KeyValue)

{

// case KEY_10: return KEY_NUM_0;//16;----0

case KEY_01: return KEY_NUM_1;//3;-----1

case KEY_02: return KEY_NUM_2;//4;-----2

case KEY_03: return KEY_NUM_3;//5;-----3

case KEY_04: return KEY_NUM_4;//7;-----4

case KEY_05: return KEY_NUM_5;//8;-----5

case KEY_06: return KEY_NUM_6;//9;-----6

case KEY_07: return KEY_NUM_7;//11----7

case KEY_08: return KEY_NUM_8;//------8

default:

return 0;

}

}

else

{

return 0;

}

}

}

else

{

KeyConter = 0; //计数清零

KeyValueBkp = 0;

}

return 0;

}

typedef struct

{

GPIO_TypeDef *port;

uint16_t pin;

}Matrix_t;

//const Matrix_t Colum1 = {GPIOD, GPIO_PIN_2};

//const Matrix_t Colum2 = {GPIOD, GPIO_PIN_3};

//const Matrix_t Colum3 = {GPIOD, GPIO_PIN_4};

const Matrix_t Colum1 = {GPIOB, GPIO_Pin_0};

const Matrix_t Colum2 = {GPIOB, GPIO_Pin_1};

const Matrix_t Colum3 = {GPIOB, GPIO_Pin_2};

const Matrix_t Colum4 = {GPIOB, GPIO_Pin_3};

const Matrix_t Line1 = {GPIOB, GPIO_Pin_4};

const Matrix_t Line2 = {GPIOB, GPIO_Pin_5};

#define KEY_01 0x1e

#define KEY_02 0x2e

#define KEY_03 0x1d

#define KEY_04 0x2d

#define KEY_05 0x1b

#define KEY_06 0x2b

#define KEY_07 0x17

#define KEY_08 0x27