**data** - up to 8 bytes of data from the CAN message's payload, represented as
a hexidecimal number in a string. Many JSON parser cannot handle 64-bit
- integers, which is why we are not using a numerical data type.
+ integers, which is why we are not using a numerical data type. Each byte in
+ 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
"pid": 5,
"payload": "0x1234",
"parse_payload": true,
+ "multiple_responses": false,
"factor": 1.0,
"offset": 0,
- "frequency": 1
+ "frequency": 1,
+ "name": "my_pid"
}
}
}
**payload** - (optional) up to 7 bytes of data for the request's payload
represented as a hexidecimal number in a string. Many JSON parser cannot
handle 64-bit integers, which is why we are not using a numerical data type.
-
-**parse_payload** - (optional, false by default) if true, the complete payload in the
- response message will be parsed as a number and returned in the 'value' field of
- the response. The 'payload' field will be omitted in responses with a
- 'value'.
+ Each byte in the string *must* be represented with 2 characters, e.g. `0x1`
+ is `0x01` - the complete string must have an even number of characters.
+
+**parse_payload** - (optional, false by default) if `true`, the complete payload
+ in the response message will be parsed as a number and returned in the
+ `value` field of the response. The `payload` field will be omitted in
+ responses with a `value`.
+
+**name** - (optional, defaults to nothing) A human readable, string name for
+ this request. If provided, the response will have a `name` field (much like a
+ normal translated message) with this value in place of `bus`, `id`, `mode` and
+ `pid`.
+
+**multiple_responses** - (optional, false by default) if true, request will stay
+ active for a full 100ms, even after receiving a diagnostic response message.
+ This is useful for requests to the functional broadcast arbitration ID
+ (`0x7df`) when you need to get responses from multiple modules. It's possible
+ to set this to `true` for non-broadcast requests, but in practice you won't
+ see any additional responses after the first and it will just take up memory
+ in the VI for longer.
**factor** - (optional, 1.0 by default) if `parse_payload` is true, the value in
the payload will be multiplied by this factor before returning. The `factor`
the only other parameter). To cancel a recurring request, send this command with
the frequency set to 0.
-TODO it'd be nice to have the OBD-II PIDs built in, with the proper conversion
-functions - that may need a different output format
-
If you're just requesting a PID, you can use this minimal field set for the
`request` object:
### Responses
+The response to a successful request:
+
{"bus": 1,
"id": 1234,
"mode": 1,
"pid": 5,
"success": true,
- "negative_response_code": 17,
"payload": "0x1234",
- "parsed_payload": 4660}
+ "value": 4660}
+
+and to an unsuccessful request, with the `negative_response_code` and no `pid`
+echo:
+
+ {"bus": 1,
+ "id": 1234,
+ "mode": 1,
+ "success": false,
+ "negative_response_code": 17}
**bus** - the numerical identifier of the CAN bus where this response was
received.
The response to a simple PID request would look like this:
- {"bus": 1, "id": 1234, "mode": 1, "pid": 5, "payload": "0x2"}
+ {"success": true, "bus": 1, "id": 1234, "mode": 1, "pid": 5, "payload": "0x2"}
+
+## Commands
+
+### Version Query
+
+The `version` command triggers the VI to inject a firmware version identifier
+response into the outgoing data stream.
+
+**Request**
+
+ { "command": "version"}
+
+**Response**
+
+ { "command_response": "version", "message": "v6.0-dev (default)"}
+
+### 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.
+
+**Request**
+
+ { "command": "device_id"}
+
+**Response**
-TODO again, it'd be nice to have the OBD-II PIDs built in, with the proper
-conversion functions so the response here included the actual transformed value
-of the pid and a human readable name
+ { "command_response": "device_id", "message": "0012345678"}
## Trace File Format