cpu_load_idle_task.c

uint32_t prev_time = get_us_ticks();
uint32_t busy_time = 0;
uint32_t total_time = 0;

while(1)
{
  uint32_t time_now = get_us_ticks();
  uint32_t delta = time_now - prev_time;
  prev_time = time_now;
  
  if (delta > 1)
  {
    busy_time += delta;
  }
  total_time += delta;
  
  if (total_time > 100000)
  {
    cpu_load = 100 * busy_time / total_time;
    busy_time = total_time = 0;
  }
}