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// vim: shiftwidth=4 tabstop=4 noexpandtab
#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/flash.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/timer.h>
#include <libopencm3/cm3/nvic.h>
static void clock_init(void);
static void gpio_init(void);
void tim2_isr(void);
static void nvic_init(void);
static void timer_init(void);
void main(void)
{
clock_init();
gpio_init();
nvic_init();
timer_init();
while(1); // wait forever
}
static void clock_init(void)
{
rcc_clock_setup_pll(&rcc_hse_configs[RCC_CLOCK_HSE8_72MHZ]);
rcc_periph_clock_enable(RCC_GPIOC); // for PC13 blinking
rcc_periph_clock_enable(RCC_TIM2); // for timer / counter 2
}
static void gpio_init(void)
{
gpio_set_mode(GPIOC,
GPIO_MODE_OUTPUT_50_MHZ,
GPIO_CNF_OUTPUT_PUSHPULL,
GPIO13);
}
void tim2_isr(void)
{
gpio_toggle(GPIOC, GPIO13);
TIM_SR(TIM2) &= ~TIM_SR_UIF; // clear interrrupt flag
}
static void nvic_init(void)
{
nvic_enable_irq(NVIC_TIM2_IRQ);
nvic_set_priority(NVIC_TIM2_IRQ, 1);
}
static void timer_init(void)
{
gpio_set(GPIOC, GPIO13);
TIM_CNT(TIM2) = 1; // set start value
TIM_PSC(TIM2) = 1440; // set prescaler
TIM_ARR(TIM2) = 50000; // interrupt value
TIM_DIER(TIM2) |= TIM_DIER_UIE; // update interrupt enable
TIM_CR1(TIM2) |= TIM_CR1_CEN; // enable timer
}
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