MSP430F149 定时器
对定时时间的说明:
当TASSEL_1时,选ACLK = 32.768KHZ,此时根据选取不同的TACCR0来实现不同的延时,
当TASSEL_2时,选SMCLK = DCO 时,~~~~~~~~~~~~~~~~~~~~~
选SMCLK = XT2时,~~~~~~~~~~~~~~~~
关键语句:
TACTL = TASSEL_X + MC_1;
TACCR0 = ~~~~~~~;
TACCTL0 = CCIE;
(3)、利用定时器A的比较模式,及输出模式4和连续计数模式可实现同时实现4个独立的定时间隔,或4种不同的频率输出。
在实验的过程中,同时驱动数码管的4个段。
在比较模式下主要区分TACCR0 TACCR1 TACCR2 及TAIFG,的中断向量及入口地址,及输出模式(共8种)
其程序如下:
#include
typedef unsigned char uchar;
typedef unsigned int uint;
uchar flag=0;
uchar table[] = {0x18,0x7e,0x51,0x52,0x36,0x92,0x90,0x5E,0x10,0x12}; //对应0---9的共阳极码
void main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
//BCSCTL1 |= XT2OFF;
//BCSCTL2 |= SELS + DIVS_3;
TACCTL0 = OUTMOD_4 +CCIE ; //Enable interrupt
TACCTL1 = OUTMOD_4 +CCIE ;
TACCTL2 = OUTMOD_4 +CCIE ;
TACCR1 = 0X8000;
TACCR2 = 0X2000;
TACCR0 = 0XF000;
P3DIR |= BIT6 + BIT7; // P3.4 output
P3OUT |= BIT6 + BIT7;
P4DIR = 0XFF;
P4OUT = 0XFF;
TACTL = TASSEL_2 + MC_2 + TAIE; // SMCLK, contmode, interrupt
_BIS_SR(LPM0_bits + GIE); // Enter LPM0 w/ interrupt
}
/**/
// Timer_A3 Interrupt Vector (TAIV) handler
#pragma vector=TIMERA1_VECTOR
__interrupt void Timer_A(void)
{
switch( TAIV )
{
case 2: P4OUT ^= BIT5; TACCR1 += 0X8000;break; // CCR1 not used
case 4: P4OUT ^= BIT3;TACCR2 += 0X2000;break; // CCR2 not used
case 10: flag++;
if(flag==12){P4OUT ^= BIT2; flag = 0; } // overflow
break;//flag++;
}
}
/**/
// Timer A0 interrupt service routine
#pragma vector=TIMERA0_VECTOR
__interrupt void Timer0_A (void)
{
P4OUT ^= BIT4; // Toggle P3.4
TACCR0 += 0XF000;
}
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