Send datagrams over a serial link (byte stream).
- Detect transmission errors (using CRC-32)
- "Hot-pluggable": automatically synchronizes with the data-stream by detecting the start of a new frame
- Low overhead
- No dynamic memory allocation
A datagram frame looks like this:
[data][CRC32][END]
The CRC32 is the "Ethernet" CRC32 (polynomial 0x104C11DB7, inverted, initialized to 0) checksum of the (unescaped) data bytes transmitted MSByte first (big-endian).
The data and CRC32 fields are escaped such that an END byte is replaced by [ESC ESC_END] and an ESC byte is replaced by [ESC ESC_ESC].
| Hex value | Abbreviation | Description |
|---|---|---|
| 0xC0 | END | Datagram End |
| 0xDB | ESC | Escape |
| 0xDC | ESC_END | Transposed End |
| 0xDD | ESC_ESC | Transposed Escape |