Deck memory - MEM_TYPE_DECK_MEM

This memory is used to access memory on decks when available. Decks that have firmware may also support firmware updates through write operations to the memory.

The information section contains information that allows a client to enumerate installed decks, identify decks with firmware that needs to be updated and the address to write new firmware to.

The information in a Deck memory info record is only valid if the Is valid bit is set to 1. The Is Valid bit is always valid, also when set to 0.

Some decks may take a while to boot, the Is started bit indicates if the deck has started and is ready. Data in the Deck memory info record should only be used if both the Is Valid and the Is started bits are set.

A deck driver may implement read and/or write operations to data on a deck, a camera deck could for instance provide image data through a memory read operation. The deck driver can freely choose the addresses where data is mapped. From a client point of view the address will be relative to the base address of the deck, the base address is acquired by a client from the information section.

If a deck has firmware upgrade capabilities, the write address for firmware upgrades must always be at 0 (relative to the base address). A deck is ready to receive FW if the Bootloader active flag is set.

The firmware that is required by a deck is uniquely identified through the tuple (required hash, required length, name).

Some decks have two hardware devices that requires two firmwares and memory mappings, like the AI deck with the ESP and the GAP8 modules. For this purpose the system supports two mappings per deck.

A deck may support commands, currently two flavors are available: reset to firmware and to bootloader. The deck signals the availability of the commands in the info bit fields.

Some decks can not be reset to bootloader mode by a client and will automatically be set in bootloader mode when the Crazyflie detects that the deck firmware is incompatible with the Crazyflie firmware.

Memory layout

Info section memory layout

Deck memory info memory layout

Addresses relative to the deck memory info base address

Deck memory info bit fields

Bit field 1:

Bit field 2:

Command section memory layout

Deck memory command data memory layout

Addresses relative to the deck memory command data base address

Deck memory command bit field

Using deck memory in a deck driver

To use the deck memory functionality, define a DeckMemDef_t struct in your deck driver.

static const DeckMemDef_t myDeckMemoryDef = {
  .write = write_mem,
  .read = read_mem,
  .properties = propertiesQuery,
  .supportsUpgrade = true,

  .requiredSize = ...,
  .requiredHash = ...,
};

and add it to the deck driver struct

static const DeckDriver my_dek = {
  // ...
  .memoryDef = &myDeckMemoryDef,
  // ...
};

Implement the propertiesQuery() function to let the system know what properties and capabilities the memory mapping for your deck supports.

Also implement the write_mem and read_mem functions as needed, depending on the capabilities of the deck.

Secondary memory mapping

Some decks have the need to support two hardware devices with two firmwares and memory mappings, like the AI deck with the ESP and the GAP8 modules. To support this, it is possible to add a second DeckMemDef_t definition:

static const DeckMemDef_t memoryDefEsp = {
  .write = write_esp,
  .read = read_esp,
  .properties = properties_esp,
  .supportsUpgrade = true,

  .requiredSize = ...,
  .requiredHash = ...,

  .id = "esp"
};

static const DeckMemDef_t memoryDefGap8 = {
  .write = write_gap8,
  .read = read_gap8,
  .properties = properties_gap8,
  .supportsUpgrade = true,

  .requiredSize = ...,
  .requiredHash = ...,

  .id = "gap8"
};

And then you can add them like:

static const DeckDriver aideck_deck = {
    .vid = 0xBC,
    .pid = 0x12,
    .name = "bcAI",

    .usedGpio = DECK_USING_IO_4,
    .usedPeriph = DECK_USING_UART1,

    .init = aideckInit,
    .test = aideckTest,

    .memoryDef = memoryDefEsp,
    .memoryDefSecondary = memoryDefGap8,
};

And the names visible to the lib would be: “bcAI:esp” and “bcAI:gap8”