PIC键盘程序

ifndef _SKEY_H_
#define _SKEY_H_
#define uchar unsigned char
#define uint unsigned int

#define SKEY_FR RA0
#define SKEY_AC RA1
#define SKEY_RDEF RA3

#define BT_FR 0X0F //REC按键值
#define BT_AC 0XF0 //AC按键值
#define BT_RDEF 0XFF //RDEF按键值
#define UNKEY 0X00 //无按键
//返回的按键值

#define SUM 16 //检测按键的总次数。每次为1ms

#define PRE 0XAA //按键按下
#define CURRENT 0X0F //释放按键

uchar read_skey(void); //返回的当前按键值

#endif

＃i nclude
＃i nclude"skey.h"

static uchar read_pre(uchar SkeyBit,uchar * SkeyCount);//读释放状态
static uchar read_current(uchar SkeyBit,uchar *SkeyCount);//读按下状态

uchar SkeyFrState=UNKEY,SkeyAcState=UNKEY,SkeyRdefState=UNKEY;
uchar FrCount,AcCount,RdefCount;
uchar FrPreCount,AcPreCount,RdefPreCount;

static void io_init()
{
ANS0 = 0; //设置AN0为数字端口
ANS1 = 0; //设置AN1为数字端口
TRISA0 = 1;
TRISA1 = 1;
TRISA3 = 1; //设置三个按键为输入
}
static uchar scan_pre(uchar SkeyBit) //扫描按下的键值
{
uchar skey_v = UNKEY;
switch(SkeyBit)
{
case BT_FR:
if(!SKEY_FR)
{
skey_v=BT_FR;
}
break;
case BT_AC:
if(!SKEY_AC)
{
skey_v=BT_AC;
}
break;
case BT_RDEF:
if(!SKEY_RDEF)
{
skey_v=BT_RDEF;
}
break;
default:break;
}
return skey_v; //按键为低电平有效
}
static uchar scan_current(uchar SkeyBit) //扫描释放的键值
{
uchar skey_v = UNKEY;
switch(SkeyBit)
{
case BT_FR:
if(SKEY_FR)
skey_v=BT_FR;
break;
case BT_AC:
if(SKEY_AC)
skey_v=BT_AC;
break;
case BT_RDEF:
if(SKEY_RDEF)
skey_v=BT_RDEF;
break;
default:break;
}
return skey_v; //释放按键为高电平有效
}

static uchar read_pre(uchar SkeyBit,uchar *SkeyCount)//参数为：需要采集的开关位
{
uchar SkeyTemp,PreState=UNKEY;//,SkeyCount;

if(*SkeyCount)
{
SkeyTemp = scan_pre(SkeyBit);
if(SkeyTemp == SkeyBit)
{
*SkeyCount += 1;
}
else
{
*SkeyCount = 0;
PreState = UNKEY;
}
}
else
{
SkeyTemp = scan_pre(SkeyBit);//采集第一个低电平
if(SkeyTemp == SkeyBit)
{
*SkeyCount = 1;
}
}
if(*SkeyCount == SUM) //完成了采集次数
{
PreState = PRE;
SkeyCount = 0;
}

return PreState;
}
static uchar read_current(uchar SkeyBit,uchar *SkeyCount)//参数：需要采集的开关位
{
uchar SkeyTemp,CurrentState=PRE;//,SkeyCount;

if(*SkeyCount)
{
SkeyTemp = scan_current(SkeyBit);
if(SkeyTemp == SkeyBit)
{
*SkeyCount += 1;
}
else
{
CurrentState = PRE;
*SkeyCount = 0;
}
}
else
{ //采集第一个高电平
SkeyTemp = scan_current(SkeyBit);
if(SkeyTemp == SkeyBit)
{
*SkeyCount = 1;
}
}

if(*SkeyCount == SUM) //完成了采集次数
{
CurrentState = CURRENT;
*SkeyCount = 0;
}

return CurrentState;
}
/*******************************************
函数名：uchar read_skey()
功能：检测并返回当前按键值
参数：无
返回值：当前按键值
编写者：
备注：read_skey()必须每5ms-30ms内，
运行一次才能正确的采集按键，并返回按键值
修改目的：实现3个按键不会相互干扰
修改日期：
*******************************************/
uchar read_skey()
{
uchar SkeyValue = UNKEY;
io_init();
if(SkeyFrState == PRE) //状态为按下
{
SkeyFrState = read_current(BT_FR,&FrCount);
}
else if(SkeyFrState == UNKEY) //状态为无按键
{
SkeyFrState = read_pre(BT_FR,&FrPreCount);
}
if(SkeyFrState == CURRENT) //状态为释放
{
SkeyValue = BT_FR;
SkeyFrState = UNKEY;
return SkeyValue;
}

if(SkeyAcState == PRE) //状态为按下
{
SkeyAcState = read_current(BT_AC,&AcCount);
}
else if(SkeyAcState == UNKEY) //状态为无按键
{
SkeyAcState = read_pre(BT_AC,&AcPreCount);
}
if(SkeyAcState == CURRENT) //状态为释放
{
SkeyValue = BT_AC;
SkeyAcState = UNKEY;
return SkeyValue;
}

if(SkeyRdefState == PRE) //状态为按下
{
SkeyRdefState = read_current(BT_RDEF,&RdefCount);
}
else if(SkeyRdefState == UNKEY) //UNKEY状态为无按键
{
SkeyRdefState = read_pre(BT_RDEF,&RdefPreCount);
}
if(SkeyRdefState == CURRENT) //状态为释放
{
SkeyValue = BT_RDEF;
SkeyRdefState = UNKEY;
return SkeyValue;
}
return SkeyValue;
}