protab/timer1-clock/timer.c

   1 #include <libopencm3/stm32/rcc.h>
   2 #include <libopencm3/stm32/gpio.h>
   3 #include <libopencm3/stm32/timer.h>
   4
   5 static void delay_ms(unsigned int ms)
   6 {
   7         timer_set_period(TIM3, 2*ms);
   8         timer_enable_counter(TIM3);
   9         while (TIM_CR1(TIM3) & TIM_CR1_CEN)
  10                 ;
  11 }
  12
  13 int main(void)
  14 {
  15         rcc_clock_setup_in_hse_8mhz_out_72mhz();
  16         rcc_periph_clock_enable(RCC_GPIOC);
  17         rcc_periph_clock_enable(RCC_TIM3);
  18
  19         // PC13 = BluePill LED
  20         gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO13);
  21
  22         timer_set_prescaler(TIM3, 35999);       // 72 MHz / 36000 = 2 kHz
  23         timer_set_mode(TIM3, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_DOWN);
  24         timer_one_shot_mode(TIM3);
  25
  26         for (;;) {
  27                 gpio_clear(GPIOC, GPIO13);
  28                 delay_ms(100);
  29                 gpio_set(GPIOC, GPIO13);
  30                 delay_ms(500);
  31         }
  32
  33         return 0;
  34 }