QuadMeUp_Crossbow
Cheap DIY RC link based on LoRa 868MHz modules
Protocol
| Byte | Description | Notes |
|---|---|---|
| 1 | Preamble | "Q" 0x51 |
| 2 | Channel ID | channel used for comunication between TX and RX |
| 3 | Frame type & Length | bits 7-5 defines frame, bits 4-0 payload length |
| 4 | Packet ID | |
| 5 - 36 | Payload | 32 bytes max |
| payload length + 5 | CRC | XOR of all previous bytes |
Frame types
| Value | Description | Direction |
|---|---|---|
| 000 | RC channels data RC_DATA |
TX -> RX |
| 001 | Receiver health and basic telemetry RX_HEALTH |
RX -> TX |
| 010 | Request receiver configuration | TX -> RX |
| 011 | Receiver configuration | RX -> TX |
| 100 | Set receiver configuration | TX -> RX |
RC_DATA frame format
Protocol allows to send 10 RC channels in total encoded as following
- channels 1 to 4 encoded using 10 bits each (5 bytes)
- channels 5 to 6 encoded using 8 bits each (2 bytes)
- channels 7 to 10 encoded using 4 bits per channel (2 bytes)
Total length of RC_DATA payload is 9 bytes
RX_HEALTH frame format
| Byte | Description |
|---|---|
| 0 | RX RSSI |
| 1 | RX supply volatage, sent in 0,1V |
| 2 | RX analog input 1 sent in 0,1V |
| 3 | RX analog input 2 sent in 0,1V |