這一靈感來源於定時器計數的方法，最後可以實現的效果跟咱們電腦鍵盤按鍵的效果一樣！我先來介紹下基本原理吧！
採用定時器中斷的方法，比如定時器終端我們設置爲5ms，我們需要按鍵按下超過40ms時纔算有按鍵按下，如果按鍵超過500ms時，我們就確定按鍵是連續按下的！
那麼我就需要一個變量來計數！每次定時器中斷時，我們就需要檢測下，某個按鍵是否按下，如果按下，那麼我們就把他對應的計數變量加1，如果這個變量等於8（8 = 40ms/5ms）時，我們就給按鍵的標誌位置爲1，如果沒有按鍵檢測到那個按鍵沒有按下，那麼我們就把他對應的按鍵標誌位清零，且他對應的計數變量清零。下面是他的流程圖！
下面具體看程序，程序裏面有說的很詳細，只是我的英語不是怎麼樣，可能寫的不是很通順，但是我確定，程序肯定是寫的令大家滿意的！希望大家多多指點！
/*
* @for Key Board
* Usage : First of All ,You Must Add Your Code to Scan Your Board Keys
* : in Function of "unsigned char GetKeyValue(void)";
* : Add function "void CheckKey(void)" into your Timer Interrupter Function;
* : Meanwhile , your should Can modify "TYPECOUNT" to change Count Range;
* : "KEYNUMBER" is a number of key;
* : "LIMITCOUNT_VALUE" is to confirm weather there is key click;
* : "MAXCOUNT_VALUE" is stand for a starting signal to repeat count;
* Author : Chen Zhenwei
* E-mail : [email protected]
* Date : 2014-04-03
* PS : My English is Poor,So There Must Be a Great Deal of Fault;
*/
/*
* @Get Key Value
* Depend on Your Board,You Must Edit By yourself;
* Return Key Value
* 0 : No Valid Key Value
* >0 : Valid Key Value
*/
unsigned char GetKeyValue(void)
{
unsigned char KeyValue = 0;
// To Add your Code to Get KeyValue
return KeyValue;
}
/*
* Define for Variable Type
* You can Set The Type of Variable According to Your Requirement;
*/
#define TYPECOUNT unsigned char // 0 ~ 255
/*
* Number of Key's Value
*/
#define KEYNUMBER 16
/*
* Limit Value of Count
* _ ____ ____________________ __ _
* ___| |_| |__| |__| |_| |______
* | | | | | | | | | | | | |
* 1 2 3 4 5 6 7 8 9 10 11 12 13
* You Can Set KEYNUMBER 6 ~ 9
*/
#define LIMITCOUNT_VALUE 20
/*
* Model of Keeping Down
* _ ____ ________________________________________________
* ___| |_| |__| ....
* | | | | | | | | | | | | | | | | ....
* 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
*/
#define MAXCOUNT_VALUE 50
/*
* Declare a Global Variable for Key Count
*/
TYPECOUNT KeyCount[KEYNUMBER];
/*
* Usage :
* Get Value : (KeyFilg & (1<<n))
* 1 : on click
* 0 : no
*/
unsigned long KeyFlag;
typedef void (*FUNC)(void * arg);
FUNC KeyFunction[KEYNUMBER]={
// Register for Key Function
// Key0
// Key1
// Add your Key Function
};
#define NULL 0x0000
/*
* To Check the Key Board
*/
void CheckKey(void)
{
unsigned char ret;
unsigned char i = 0;
ret = GetKeyValue();
for(i=0; i<KEYNUMBER; i++){
if(i+1 == ret){
// Count for Key Which is on Clicking
KeyCount[i] ++;
}
else{
// Clear Key Flag And Count
KeyCount[i] = 0;
KeyFlag &= ~(1<<i);
}
if(KeyCount[i] == LIMITCOUNT_VALUE){
// Set Key Flag '1'
KeyFlag |= (1<<i);
// Do Your Given Key Function
KeyFunction[i](NULL);
}
if(KeyCount[i] > MAXCOUNT_VALUE){
KeyCount[i] = 0;
KeyFlag &= ~(1<<i);
}
}
}
/*
* Key Status
*/
#define KEYDOWN 1L
#define KEYUP 0L
/*
* You Can Use GetKeyStatus(i) to Get The Key Status;
* And In Here , You Don't Need to Care About to Clear the Key Flag,
* Because It Will Be Auto to Clear the Key Flag.
*/
unsigned char GetKeyStatus(unsigned char KeyNumber)
{
unsigned long Status;
// Get Status of KeyNumber
Status = KeyFlag&(1<<KeyNumber);
// Clear Key Flag
KeyFlag &= ~(1<<KeyNumber);
return (Status ? KEYDOWN : KEYUP);
}轉載聲明：http://blog.csdn.net/ieczw/article/details/22926523