02-usart/src/main.c


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#include "arch.h"
#include "core/clock.h"
#include "core/dma.h"
#include "core/gpio.h"
#include "core/isr_vector.h"
#include "core/system.h"
#include "core/usart.h"

#include "delay.h"
#include "lib.h"
#include "mem.h"
#include "spin.h"
#include "string.h"


#ifdef ARCH_STM32L4

/** Overrides the default systick irq handler. */
void on_systick()
{
  static int is_on = 0;

  __IO gpio_port_t* port_b = enable_gpio(GPIO_PORT_B);
  gpio_output_pin_t pin3 = set_gpio_pin_output(port_b, PIN_3);

  if (is_on) {
    pin_off(pin3);
  } else {
    pin_on(pin3);
  }

  is_on = ! is_on;
}

/* Main function. This gets executed from the interrupt vector defined above. */
int main()
{
  /* Enable a higher clock frequency. */
  set_system_clock_MHz(80);

  /* Set the countdown to start from 1,000,0000. */
  SCB.strv_r = 10000000;

  /* Enable interrupts. */
  SCB.stcs_bf.tickint = 1;

  /* Start the systick. */
  SCB.stcs_bf.enable = 1;
}

#endif