MSP430 G2553用于IR接收器的TimerA比较模式

时间:2017-06-23 09:59:10

标签: timer msp430 receiver infrared

我的IR接收器在P1.1上发送数字数据。我已经配置了定时器,如果有下降或上升沿,则会触发中断。我想知道如何获得边缘之间的实际时间。之后我想把它们保存在阵列中。

主:

// Stop watchdog timer
WDTCTL = WDTPW + WDTHOLD;

//1mhz = 0.000001
BCSCTL1 = CALBC1_1MHZ;               // load calibrated data
DCOCTL = CALDCO_1MHZ;

//Define Outputs
P1DIR = green_led+red_led+IR_Send;
P2DIR = LED1+LED2+LED3;

//Define Inputs
P1DIR &= ~IR_Recv;

//Set IR_Recv as input for Timer (TA0.CCI0A)
P1SEL |= BIT1;

//Timer_A using SMCLK/8 = 0.000008s and Continuous mode
TACTL = TASSEL_2 | MC_2 | ID_3;

// falling edge and rising edge capture mode, CCI0A, enable IE
CCTL0 = CM_3 | CCIS_0 | CAP | CCIE;

//Enter LPM and enable Global Interrupts
__bis_SR_register(CPUOFF + GIE);

中断例程:

//gets called when falling or rising edge is detected on IR_Recv
#pragma vector = TIMER0_A0_VECTOR
__interrupt void Timer_A (void)
{
if(edgeCount < 10){
    rxData[edgeCount] = TACCR0;
    TACCR0 = 0;
}
edgeCount++;

P2OUT ^= LED2;
//Clear interrupt Flag
TACCTL0 &= ~CCIFG;
//go back to LPM
__bic_SR_register_on_exit ( CPUOFF );
}

1 个答案:

答案 0 :(得分:1)

要获得两个捕获事件之间的时间差(以刻度表示),只需让计时器继续运行而不重置它,然后减去捕获的时间戳:

NULL

即使定时器计数器发生溢出,该计算也是正确的。