我们用定时器做个40ms的定时。
定时器的计数周期为SMCLK/8,其中SMCLK=12M.
所以定时40ms需要计数60000次
定时器初始化：
- void timer_init(void)
- {
- TIMER_A0->CCTL[0] = TIMER_A_CCTLN_CCIE; // TACCR0 interrupt enabled
- TIMER_A0->CCR[0] = 60000;//40ms
- TIMER_A0->CTL = TIMER_A_CTL_SSEL__SMCLK | // SMCLK, continuous mode
- TIMER_A_CTL_MC__CONTINUOUS|
- TIMER_A_CTL_ID_3;//SMCLK/8 =1.5M
- NVIC->ISER[0] |= 1 << ((TA0_0_IRQn) & 31);//使能中断
- }
- // Timer A0 interrupt service routine
- void TA0_0_IRQHandler(void) {
- TIMER_A0->CCTL[0] &= ~TIMER_A_CCTLN_CCIFG;
- P1->OUT ^= BIT0;//翻转LED灯
- TIMER_A0->CCR[0] = 60000; // Add Offset to TACCR0
- }
- int main(void)
- {
- WDT_A->CTL = WDT_A_CTL_PW | // Stop watchdog timer
- WDT_A_CTL_HOLD;
- clk_init();//clk init
- uart_init();//uart init,9600
- timer_init();
- GPIO_setAsOutputPin(GPIO_PORT_P1,GPIO_PIN0);//设置P1.0为输出
- //sprintf((char *)ptr,"%.2f\r\n",a);
-
- //printf("test...\r\n");
- while(1)
- {
- jansson_pack_test();
- //GPIO_toggleOutputOnPin(GPIO_PORT_P1,GPIO_PIN0);
- for(int i=0;i<100000;i++)
- {;}
- }
- }
实际的现象也是led灯进行周期性翻转。
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楼主
