tool/mbed/mbed-sdk/libraries/tests/KL25Z/lptmr/main.cpp

   1 #include "mbed.h"
   2
   3 volatile unsigned int ticks = 0;
   4
   5 DigitalOut led(LED_BLUE);
   6
   7 extern "C" void lptmr_isr(void) {
   8     // write 1 to TCF to clear the LPT timer compare flag
   9     LPTMR0->CSR |= LPTMR_CSR_TCF_MASK;
  10
  11     ticks++;
  12 }
  13
  14 int main() {
  15     /* Clock the timer */
  16     SIM->SCGC5 |= SIM_SCGC5_LPTMR_MASK;
  17
  18     /* Reset */
  19     LPTMR0->CSR = 0;
  20
  21     /* Compare value */
  22     LPTMR0->CMR = 1000;
  23
  24     /* Enable interrupt */
  25     LPTMR0->CSR |= LPTMR_CSR_TIE_MASK;
  26
  27     /* Set interrupt handler */
  28     NVIC_SetVector(LPTimer_IRQn, (uint32_t)lptmr_isr);
  29     NVIC_EnableIRQ(LPTimer_IRQn);
  30
  31     /* select LPO for RTC and LPTMR */
  32     LPTMR0->PSR = LPTMR_PSR_PCS(3);       // ERCLK32K -> 8MHz
  33     LPTMR0->PSR |= LPTMR_PSR_PRESCALE(2); // divide by 8
  34
  35     /* Start the timer */
  36     LPTMR0->CSR |= LPTMR_CSR_TEN_MASK;
  37
  38     led = 0;
  39     while (true) {
  40         wait(1);
  41         led = 1;
  42         printf("%d\n", ticks);
  43
  44         wait(1);
  45         led = 0;
  46         printf("%d\n", ticks);
  47     }
  48 }