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Diffstat (limited to 'README.md')
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1 files changed, 17 insertions, 13 deletions
@@ -7,15 +7,19 @@ This specification is a part of the [OpenXC platform][OpenXC]. An OpenXC vehicle interface sends generic vehicle data over one or more output interfaces (e.g. USB or Bluetooth) as JSON or Protocol Buffers (protobuf). -This document describes the JSON format and includes a high level description of -each type and field. Each JSON message published by a VI is delimited with a -`\0` character. +## Binary (Protocol Buffers) The Protocol Buffer format is specified in the file `openxc.proto`. Those are published using the standard length-delimited method (any protobuf library should support this). -## Single Valued +## JSON + +This document describes the JSON format and includes a high level description of +each type and field. Each JSON message published by a VI is delimited with a +`\0` character. + +### Single Valued There may not be a 1:1 relationship between input and output signals - i.e. raw engine timing CAN signals may be summarized in an "engine performance" metric on @@ -25,7 +29,7 @@ The expected format of a single valued message is: {"name": "steering_wheel_angle", "value": 45} -## Evented +### Evented The expected format of an event message is: @@ -34,7 +38,7 @@ The expected format of an event message is: This format is good for something like a button event, where there are two discrete pieces of information in the measurement. -## Raw CAN Message format +### Raw CAN Message format The format for a raw CAN message: @@ -51,9 +55,9 @@ The format for a raw CAN message: the string *must* be represented with 2 characters, e.g. `0x1` is `0x01` - the complete string must have an even number of characters. -## Diagnostic Messages +### Diagnostic Messages -### Requests +#### Requests A request to add or update a diagnostic request is sent to a vehicle interface with this command format: @@ -134,7 +138,7 @@ If you're just requesting a PID, you can use this minimal field set for the {"bus": 1, "id": 1234, "mode": 1, "pid": 5} -### Responses +#### Responses The response to a successful request: @@ -185,9 +189,9 @@ The response to a simple PID request would look like this: {"success": true, "bus": 1, "id": 1234, "mode": 1, "pid": 5, "payload": "0x2"} -## Commands +### Commands -### Version Query +#### Version Query The `version` command triggers the VI to inject a firmware version identifier response into the outgoing data stream. @@ -200,7 +204,7 @@ response into the outgoing data stream. { "command_response": "version", "message": "v6.0-dev (default)"} -### Device ID Query +#### Device ID Query The `device_id` command triggers the VI to inject a unique device ID (e.g. the MAC address of an included Bluetooth module) into into the outgoing data stream. @@ -213,7 +217,7 @@ MAC address of an included Bluetooth module) into into the outgoing data stream. { "command_response": "device_id", "message": "0012345678"} -## Trace File Format +### Trace File Format An OpenXC vehicle trace file is a plaintext file that contains JSON objects, separated by newlines (which may be either `\r\n` or `\n`, depending on the |