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This page has deprecated and moved to the new documentation framework of the main Bitcraze website. Please go to [[https://www.bitcraze.io/documentation/system/]]
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====== Deck API ======

The Deck API allows to easily communicates with decks installed on the Crazyflie. The deck API is still in development, it will:

  * Enumerates installed Deck and initialize drivers (//pretty much done//)
  * Provides easy to use arduino-like API to access (//started//)
  * Optionally provides a task to run in (arduino-like setup and loop) (//not started yet//)

If you want to get started you can follow the [[doc:crazyflie:api:firmware:deck:howto|howto]] to get your code running.
===== Deck drivers =====

Decks are enumerated automatically using a One Wire (OW) memory soldered on
the deck PCB. The Deck driver API is using a declarative syntax to register
deck drivers and initialize them when the proper deck is installed.

==== Minimal driver ====

This is a minimal deck driver, myled.c:

<code c>
#include "deck.h"

void myledInit(DeckInfo *info)
{
  pinMode(DECK_GPIO_IO1, OUTPUT);     // Set my Led pin to output
  digitalWrite(DECK_GPIO_IO1, HIGH);  // Light it up
}

bool myledTest()
{
  return true;
}

const DeckDriver myled_driver = {
  .vid = 0,
  .pid = 0,
  .name = "meMyled",


  .usedGpio = DECK_USING_IO_1,

  .init = myledInit,
  .test = myledTest,
};

DECK_DRIVER(myled_driver);
</code>

  * At startup the decks are enumerated and if a deck has the name "meMyled", it will be initialized.
  * Init is called on all initialized driver and then test is called.
  * The init and test functions are both optional (we have some board with only init and event some with only test). If absent just remove the //.init// or //.test// initialisation.
  * In this mode no task are created so to run some code at regular intervale the code needs to deal with freeRtos or with the other parts of the Crazyflie code.

To compile the driver, place it in deck/drivers/src/ and add it to the Makefile:

<code make>
PROJ_OBJ += myled.o
</code>

==== Forcing initialization of a driver ====

The deck driver will be initialized only if a deck is connected with the right
OW memory content. During development it is possible to force the initialisation
of a deck by adding a define in ```tools/make/config.mk```:

<code make>
CFLAGS += -DDECK_FORCE=meMyled
</code>

==== Driver declaration API ====

//DECK_DRIVER(const struct DeckDriver)//

To register a deck driver the DECK_DRIVER() macro should be called with a deck
structure as argument.

=== DeckDriver structure ===

<code c>
typedef struct deck_driver {
  /* Identification of the deck (written in the board) */
  uint8_t vid;
  uint8_t pid;
  char *name;

  /* Periphreal and Gpio used _dirrectly_ by the driver */
  uint32_t usedPeriph;
  uint32_t usedGpio;

  /* Init and test functions */
  void (*init)(struct deckInfo_s *);
  bool (*test)(void);
} DeckDriver;
</code>