/** Semaphore to arbitrate access to the display. */
static struct Semaphore lcd_semaphore;
#define LOCK_LCD sem_obtain(&lcd_semaphore)
#define UNLOCK_LCD sem_release(&lcd_semaphore)
/** Semaphore to arbitrate access to the display. */
static struct Semaphore lcd_semaphore;
#define LOCK_LCD sem_obtain(&lcd_semaphore)
#define UNLOCK_LCD sem_release(&lcd_semaphore)