Lee Kai Xuan / mbed-os

mbed-os

Fork of mbed-os by erkin yucel

features/unsupported/tests/KL25Z/pit/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 extern "C" {
elessair 0:f269e3021894 4 volatile uint32_t msTicks;
elessair 0:f269e3021894 5
elessair 0:f269e3021894 6 void SysTick_Handler(void) {
elessair 0:f269e3021894 7 msTicks++;
elessair 0:f269e3021894 8 }
elessair 0:f269e3021894 9
elessair 0:f269e3021894 10 void Delay(uint32_t dlyTicks) {
elessair 0:f269e3021894 11 uint32_t curTicks;
elessair 0:f269e3021894 12
elessair 0:f269e3021894 13 curTicks = msTicks;
elessair 0:f269e3021894 14 while ((msTicks - curTicks) < dlyTicks);
elessair 0:f269e3021894 15 }
elessair 0:f269e3021894 16 }
elessair 0:f269e3021894 17
elessair 0:f269e3021894 18 int main() {
elessair 0:f269e3021894 19 SysTick_Config(SystemCoreClock / 1000);
elessair 0:f269e3021894 20
elessair 0:f269e3021894 21 SIM->SCGC6 |= SIM_SCGC6_PIT_MASK; // Clock PIT
elessair 0:f269e3021894 22 PIT->MCR = 0; // Enable PIT
elessair 0:f269e3021894 23
elessair 0:f269e3021894 24 // Timer 1
elessair 0:f269e3021894 25 PIT->CHANNEL[1].LDVAL = 0xFFFFFFFF;
elessair 0:f269e3021894 26 PIT->CHANNEL[1].TCTRL = 0x0; // Disable Interrupts
elessair 0:f269e3021894 27 PIT->CHANNEL[1].TCTRL |= PIT_TCTRL_CHN_MASK; // Chain to timer 0
elessair 0:f269e3021894 28 PIT->CHANNEL[1].TCTRL |= PIT_TCTRL_TEN_MASK; // Start timer 1
elessair 0:f269e3021894 29
elessair 0:f269e3021894 30 // Timer 2
elessair 0:f269e3021894 31 PIT->CHANNEL[0].LDVAL = 0xFFFFFFFF;
elessair 0:f269e3021894 32 PIT->CHANNEL[0].TCTRL = PIT_TCTRL_TEN_MASK; // Start timer 0, disable interrupts
elessair 0:f269e3021894 33
elessair 0:f269e3021894 34 DigitalOut led(LED_BLUE);
elessair 0:f269e3021894 35 while (true) {
elessair 0:f269e3021894 36 Delay(1000);
elessair 0:f269e3021894 37 led = !led;
elessair 0:f269e3021894 38
elessair 0:f269e3021894 39 uint64_t ticks = (uint64_t)PIT->LTMR64H << 32;
elessair 0:f269e3021894 40 ticks |= (uint64_t)PIT->LTMR64L;
elessair 0:f269e3021894 41 printf("ticks: 0x%x%x\n", (uint32_t)(ticks>>32), (uint32_t)(ticks & 0xFFFFFFFF));
elessair 0:f269e3021894 42
elessair 0:f269e3021894 43 ticks = (~ticks) / 24;
elessair 0:f269e3021894 44 uint32_t us = (uint32_t)(0xFFFFFFFF & ticks);
elessair 0:f269e3021894 45
elessair 0:f269e3021894 46 printf("us : 0x%x\n", us);
elessair 0:f269e3021894 47 }
elessair 0:f269e3021894 48 }