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