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

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