Aerial protocol definition and implementation. This protocol is used for all communication tasks from the ground station to the aerial vehicle. It is designed with the following goals:
- Low decoding and encoding overhead
- Space efficient
- Tolerant of transmission errors
- Platform independent
A complete transmission is referred to as a message. A message is composed of a marker byte, a message ID, and a payload. The format is as follows:
| Data | Type | Description |
|---|---|---|
| 0x67 | u8 | Marks the beginning of a message |
| .... | u8 | Message ID |
| .... | [u8, ..len] | Payload |
The following byte values are reserved in the protocol. If used in a message payload they must be preceded by an escape character.
| Value | Name |
|---|---|
| 0x67 | START |
| 0x68 | ESCAPE |
Below is an example transmission sequence. After receiving each byte, the state to which the decoder will transition to is shown.
| Data | Decoder State |
|---|---|
| .... | WAIT_HEADER |
| 0x67 | WAIT_ID |
| 0x01 | IN_MESSAGE |
| 0x05 | IN_MESSAGE |
| 0x06 | IN_MESSAGE |
| 0x68 | AFTER_ESC |
| 0x67 | IN_MESSAGE |
| 0x80 | IN_MESSAGE |
| 0x81 | WAIT_HEADER |