# `MAVLink2.Dialect`
[🔗](https://github.com/isaiahdw/mavlink2/blob/v0.1.0/lib/mavlink2/dialect.ex#L1)

A MAVLink dialect: for each message id, the `crc_extra` byte the checksum
ends with and the payload length the receiver zero-extends to.

`MAVLink2.Frame` and `MAVLink2.Link` take the dialect as a module. Both
return `nil` for an id the dialect does not have.

`target_offsets/1` is optional: for a message with `target_system` or
`target_component` fields, their byte offsets in the payload, `nil` for a
field the message lacks. `MAVLink2.Router` uses it; without it, every
message without a header target is a broadcast.

# `crc_extra`

```elixir
@callback crc_extra(msgid :: non_neg_integer()) :: 0..255 | nil
```

# `payload_length`

```elixir
@callback payload_length(msgid :: non_neg_integer()) :: pos_integer() | nil
```

# `target_offsets`
*optional* 

```elixir
@callback target_offsets(msgid :: non_neg_integer()) ::
  {system :: non_neg_integer() | nil, component :: non_neg_integer() | nil}
```

---

*Consult [api-reference.md](api-reference.md) for complete listing*