＃i nclude <msp430x14x.h>

void Init_Port(void)

{

//将P1口所有的管脚在初始化的时候设置为输入方式

P1DIR = 0;

//将P1口所有的管脚设置为一般I/O口

P1SEL = 0;

// 将P1.4 P1.5 P1.6 P1.7设置为输出方向

P1DIR |= BIT4;

P1DIR |= BIT5;

P1DIR |= BIT6;

P1DIR |= BIT7;

//先输出低电平

P1OUT = 0x00;

// 将中断寄存器清零

P1IE = 0;

P1IES = 0;

P1IFG = 0;

//打开管脚的中断功能

//对应的管脚由高到低电平跳变使相应的标志置位

P1IE |= BIT0;

P1IES |= BIT0;

P1IE |= BIT1;

P1IES |= BIT1;

P1IE |= BIT2;

P1IES |= BIT2;

P1IE |= BIT3;

P1IES |= BIT3;

_EINT();//打开中断

return;

}

void Delay(void)

{

int i;

for(i = 100;i--;i > 0) ;//延时一点时间

}

int KeyProcess(void)

{

int nP10,nP11,nP12,nP13;

int nRes = 0;

//P1.4输出低电平

P1OUT &= ~(BIT4);

nP10 = P1IN & BIT0;

if (nP10 == 0) nRes = 13;

nP11 = P1IN & BIT1;

if (nP11 == 0) nRes = 14;

nP12 = P1IN & BIT2;

if (nP12 == 0) nRes = 15;

nP13 = P1IN & BIT3;

if (nP13 == 0) nRes = 16;

//P1.5输出低电平

P1OUT &= ~(BIT4);

nP10 = P1IN & BIT0;

if (nP10 == 0) nRes = 9;

nP11 = P1IN & BIT1;

if (nP11 == 0) nRes = 10;

nP12 = P1IN & BIT2;

if (nP12 == 0) nRes = 11;

nP13 = P1IN & BIT3;

if (nP13 == 0) nRes = 12;

//P1.6输出低电平

P1OUT &= ~(BIT4);

nP10 = P1IN & BIT0;

if (nP10 == 0) nRes = 5;

nP11 = P1IN & BIT1;

if (nP11 == 0) nRes = 6;

nP12 = P1IN & BIT2;

if (nP12 == 0) nRes = 7;

nP13 = P1IN & BIT3;

if (nP13 == 0) nRes = 8;

//P1.7输出低电平

P1OUT &= ~(BIT4);

nP10 = P1IN & BIT0;

if (nP10 == 0) nRes = 1;

nP11 = P1IN & BIT1;

if (nP11 == 0) nRes = 2;

nP12 = P1IN & BIT2;

if (nP12 == 0) nRes = 3;

nP13 = P1IN & BIT3;

if (nP13 == 0) nRes = 4;

P1OUT = 0x00;//恢复以前值。

//读取各个管脚的状态

nP10 = P1IN & BIT0;

nP11 = P1IN & BIT1;

nP12 = P1IN & BIT2;

nP13 = P1IN & BIT3;

for(;;)

{

if(nP10 == 1 && nP11 == 1 && nP12 == 1 && nP13 == 1)

{

//等待松开按键

break;

}

}

return nRes;

}

// 处理来自端口 1 的中断

interrupt [PORT1_VECTOR] void PORT_ISR(void)

{

Delay();

KeyProcess();

if(P1IFG & BIT0)

{

P1IFG &= ~(BIT0);// 清除中断标志位

}

if(P1IFG & BIT1)

{

P1IFG &= ~(BIT1);// 清除中断标志位

}

if(P1IFG & BIT2)

{

P1IFG &= ~(BIT2);// 清除中断标志位

}

if(P1IFG & BIT3)

{

P1IFG &= ~(BIT3);// 清除中断标志位

}

}

void Init_CLK(void)

{

unsigned int i;

BCSCTL1 = 0X00;//将寄存器的内容清零

//XT2震荡器开启

//LFTX1工作在低频模式

//ACLK的分频因子为1

do

{

IFG1 &= ~OFIFG; // 清除OSCFault标志

for (i = 0x20; i > 0; i--);

}

while ((IFG1 & OFIFG) == OFIFG); // 如果OSCFault =1

BCSCTL2 = 0X00;//将寄存器的内容清零

BCSCTL2 += SELM1;//MCLK的时钟源为TX2CLK，分频因子为1

BCSCTL2 += SELS;//SMCLK的时钟源为TX2CLK，分频因子为1

}

MSP430按键接口电路图