20 lines
835 B
Markdown
20 lines
835 B
Markdown
# UART Protocol
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If enabled using the `TODO` feature flag, all received messages are transmitted on UART using the protocol described in this document.
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The serial communication can also be used to send V2X data.
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## Message Format
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The UART communication is using a custom framing protocol to encapsulate binary messages.
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The payload is:
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- a `SerialOutputMsg` for transmissions from the ESP to the host or
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- a `SerialInputMsg` for transmissions from the host to the ESP
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in binary [Proto](https://protobuf.dev/) serialization according to the [c_its-messages.proto](./c_its-messages.proto) definition.
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Each transmission:
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- starts with a Start of Frame (SOF) sequence: `0x56, 0x32, 0x58, 0x2B` ("V2X+")
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- followed by a 16-bit big-endian length field
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- followed by the payload
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- followed by an End of Frame (EOF) sequence `0x0d, 0x0a`
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