FAQ – Lehrstuhl für Informatik 4

libspicboard
 #ifndef LED_H
 #define LED_H
  
 #include <stdint.h>
 #include "check.h"
  
 /**
  * \addtogroup LED LED access
  *
  * \brief Interface to the board's 8 LEDs
  *
  * @{
  * \file led.h
  * \version \$Rev: 7715 $
  */
  
 /**
  * \brief LED identifiers
  */
 typedef enum {
     RED0    = 0, /**< Upper red led    **/
     YELLOW0 = 1, /**< Upper yellow led **/
     GREEN0  = 2, /**< Upper green led  **/
     BLUE0   = 3, /**< Upper blue led   **/
     RED1    = 4, /**< Lower red led    **/
     YELLOW1 = 5, /**< Lower yellow led **/
     GREEN1  = 6, /**< Lower green led  **/
     BLUE1   = 7  /**< Lower blue led   **/
 }  __attribute__ ((__packed__)) LED;
  
 CHECK_ENUM_SIZE(LED, 1)
  
 /**
  * \brief Activates a specific LED
  *
  * \param led  LED ID
  *
  * \return 0 on success, negative value on error
  *
  * \retval  0  success
  * \retval -1  invalid LED ID
  */
 int8_t sb_led_on(LED led);
  
 /**
  * \brief Deactivates a specific LED
  *
  * \param led  LED ID
  *
  * \return 0 on success, negative value on error
  *
  * \retval  0  success
  * \retval -1  invalid LED ID
  */
 int8_t sb_led_off(LED led);
  
 /**
  * \brief Toggles a specific LED
  *
  * \param led  LED ID
  *
  * \return 0 on success, negative value on error
  *
  * \retval  0  success
  * \retval -1  invalid LED ID
  */
 int8_t sb_led_toggle(LED led);
  
 /**
  * \brief Uses the LED array as a level indicator
  *
  * Allows the array of LEDs to be used as a (fill) level, progress
  * or similar indicator. The 8 LEDs are used to display a ratio of
  * a max-value<=255 in 9 steps.
  *
  * \param level  level value
  * \param max    maximum possible value
  *
  * \return the number of LEDs turned on on success, negative value on error
  *
  * \retval >=0  success
  * \retval -1   level exceeds max
  * \retval -2   max is 0
  */
 int8_t sb_led_showLevel(uint8_t level, uint8_t max);
  
 /**
  * \brief Sets all LEDs according to a bitfield
  *
  * The bitfield contains one bit for each LED (the least significant bit
  * corresponds to `RED0`, the most significant bit `BLUE1`). A set bit
  * enables and a cleared bit disables the corresponding LED.
  * \image html led_mask.png
  * \param mask  8-bit bitfield describing the desired LED states
  */
 void sb_led_setMask(uint8_t mask);
  
 /** @}*/
  
 #endif
  