Elaborate on 'name' field for diagnostic requests.

[apps/agl-service-can-low-level.git] / README.md

diff --git a/README.md b/README.md
index a10fe88..cef6ea3 100644 (file)
--- a/README.md
+++ b/README.md
@@ -40,7 +40,9 @@ is sent as a JSON object, separated by newlines. The format of each object is:
 
 **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
 
@@ -57,9 +59,11 @@ with this command format:
           "pid": 5,
           "payload": "0x1234",
           "parse_payload": true,
+          "multiple_responses": false,
           "factor": 1.0,
           "offset": 0,
-          "frequency": 1
+          "frequency": 1,
+          "name": "my_pid"
         }
       }
     }
@@ -77,11 +81,26 @@ with this command format:
 **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`
@@ -94,8 +113,10 @@ with this command format:
 **frequency** - (optional, defaults to 0) The frequency in Hz to send this
     request. To send a single request, set this to 0 or leave it out.
 
-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
+The `bus+id+mode+pid` key is unique, so if you send a create request with that
+key twice, it'll overwrite the existing one (i.e. it will change the frequency,
+the only other parameter). To cancel a recurring request, send this command with
+the frequency set to 0.
 
 If you're just requesting a PID, you can use this minimal field set for the
 `request` object:
@@ -104,14 +125,24 @@ If you're just requesting a PID, you can use this minimal field set for the
 
 ### 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.
@@ -142,11 +173,35 @@ Finally, the `payload` and `value` fields are mutually exclusive:
 
 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