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Diffstat (limited to 'examples/stm32/f1/other/timer_interrupt/timer.c')
-rw-r--r--examples/stm32/f1/other/timer_interrupt/timer.c36
1 files changed, 18 insertions, 18 deletions
diff --git a/examples/stm32/f1/other/timer_interrupt/timer.c b/examples/stm32/f1/other/timer_interrupt/timer.c
index 422df88..b523503 100644
--- a/examples/stm32/f1/other/timer_interrupt/timer.c
+++ b/examples/stm32/f1/other/timer_interrupt/timer.c
@@ -35,51 +35,51 @@ void gpio_setup(void)
GPIO_CNF_OUTPUT_PUSHPULL, GPIO7);
}
-void nvic_setup()
+void nvic_setup(void)
{
- /* without this the timer interrupt routine will never be called */
+ /* Without this the timer interrupt routine will never be called. */
nvic_enable_irq(NVIC_TIM2_IRQ);
- nvic_set_priority(NVIC_TIM2_IRQ, 1);
+ nvic_set_priority(NVIC_TIM2_IRQ, 1);
}
-void tim2_isr()
+void tim2_isr(void)
{
- /* LED2 on/off */
- gpio_toggle(GPIOB, GPIO6);
-
- /* clear interrrupt flag */
- TIM_SR(TIM2) &= ~TIM_SR_UIF;
+ gpio_toggle(GPIOB, GPIO6); /* LED2 on/off. */
+ TIM_SR(TIM2) &= ~TIM_SR_UIF; /* Clear interrrupt flag. */
}
int main(void)
{
- rcc_clock_setup_in_hse_16mhz_out_72mhz();
+ rcc_clock_setup_in_hse_16mhz_out_72mhz();
gpio_setup();
nvic_setup();
gpio_clear(GPIOB, GPIO7); /* LED1 on */
gpio_set(GPIOB, GPIO6); /* LED2 off */
-
+
rcc_peripheral_enable_clock(&RCC_APB1ENR, RCC_APB1ENR_TIM2EN);
- /* the goal is to let the LED2 glow for a second and then be off for a second */
+ /*
+ * The goal is to let the LED2 glow for a second and then be
+ * off for a second.
+ */
- /* Set timer start value */
+ /* Set timer start value. */
TIM_CNT(TIM2) = 1;
- /* Set timer prescaler. 72MHz/1440 => 50000 counts per second */
+ /* Set timer prescaler. 72MHz/1440 => 50000 counts per second. */
TIM_PSC(TIM2) = 1440;
- /* End timer value. If this value is reached an interrupt is generated */
+ /* End timer value. If this is reached an interrupt is generated. */
TIM_ARR(TIM2) = 50000;
- /* Update interrupt enable */
+ /* Update interrupt enable. */
TIM_DIER(TIM2) |= TIM_DIER_UIE;
- /* Start timer */
+ /* Start timer. */
TIM_CR1(TIM2) |= TIM_CR1_CEN;
- while(1); /* Halt. */
+ while (1); /* Halt. */
return 0;
}