Lee Kai Xuan / mbed-os

mbed-os

Fork of mbed-os by erkin yucel

features/unsupported/tests/KL25Z/lptmr/main.cpp@0:f269e3021894, 2016-10-23 (annotated)

Committer:
elessair
Date:
Sun Oct 23 15:10:02 2016 +0000
Revision:
0:f269e3021894
Initial commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
elessair 0:f269e3021894 1 #include "mbed.h"
elessair 0:f269e3021894 2
elessair 0:f269e3021894 3 volatile unsigned int ticks = 0;
elessair 0:f269e3021894 4
elessair 0:f269e3021894 5 DigitalOut led(LED_BLUE);
elessair 0:f269e3021894 6
elessair 0:f269e3021894 7 extern "C" void lptmr_isr(void) {
elessair 0:f269e3021894 8 // write 1 to TCF to clear the LPT timer compare flag
elessair 0:f269e3021894 9 LPTMR0->CSR |= LPTMR_CSR_TCF_MASK;
elessair 0:f269e3021894 10
elessair 0:f269e3021894 11 ticks++;
elessair 0:f269e3021894 12 }
elessair 0:f269e3021894 13
elessair 0:f269e3021894 14 int main() {
elessair 0:f269e3021894 15 /* Clock the timer */
elessair 0:f269e3021894 16 SIM->SCGC5 |= SIM_SCGC5_LPTMR_MASK;
elessair 0:f269e3021894 17
elessair 0:f269e3021894 18 /* Reset */
elessair 0:f269e3021894 19 LPTMR0->CSR = 0;
elessair 0:f269e3021894 20
elessair 0:f269e3021894 21 /* Compare value */
elessair 0:f269e3021894 22 LPTMR0->CMR = 1000;
elessair 0:f269e3021894 23
elessair 0:f269e3021894 24 /* Enable interrupt */
elessair 0:f269e3021894 25 LPTMR0->CSR |= LPTMR_CSR_TIE_MASK;
elessair 0:f269e3021894 26
elessair 0:f269e3021894 27 /* Set interrupt handler */
elessair 0:f269e3021894 28 NVIC_SetVector(LPTimer_IRQn, (uint32_t)lptmr_isr);
elessair 0:f269e3021894 29 NVIC_EnableIRQ(LPTimer_IRQn);
elessair 0:f269e3021894 30
elessair 0:f269e3021894 31 /* select LPO for RTC and LPTMR */
elessair 0:f269e3021894 32 LPTMR0->PSR = LPTMR_PSR_PCS(3); // ERCLK32K -> 8MHz
elessair 0:f269e3021894 33 LPTMR0->PSR |= LPTMR_PSR_PRESCALE(2); // divide by 8
elessair 0:f269e3021894 34
elessair 0:f269e3021894 35 /* Start the timer */
elessair 0:f269e3021894 36 LPTMR0->CSR |= LPTMR_CSR_TEN_MASK;
elessair 0:f269e3021894 37
elessair 0:f269e3021894 38 led = 0;
elessair 0:f269e3021894 39 while (true) {
elessair 0:f269e3021894 40 wait(1);
elessair 0:f269e3021894 41 led = 1;
elessair 0:f269e3021894 42 printf("%d\n", ticks);
elessair 0:f269e3021894 43
elessair 0:f269e3021894 44 wait(1);
elessair 0:f269e3021894 45 led = 0;
elessair 0:f269e3021894 46 printf("%d\n", ticks);
elessair 0:f269e3021894 47 }
elessair 0:f269e3021894 48 }