more gears

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

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+++ b/README.md
@@ -1,5 +1,10 @@
 # OpenXC Message Format Specification
 
+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 objects, separated by newlines.
+
 There are two valid message types - single valued and evented.
 
 There may not be a 1:1 relationship between input and output signals - i.e. raw
@@ -20,3 +25,128 @@ 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
+
+An OpenXC vehicle interface may also output raw CAN messages. Each CAN message
+is sent as a JSON object, separated by newlines. The format of each object is:
+
+    {"bus": 1, "id": 1234, "value": "0x12345678"}
+
+**bus** - the numerical identifier of the CAN bus where this message originated,
+  most likely 1 or 2 (for a vehicle interface with 2 CAN controllers).
+
+**id** - the CAN message ID
+
+**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.
+
+## Trace File Format
+
+An OpenXC vehicle trace file is a plaintext file that contains JSON objects,
+separated by newlines.
+
+The first line may be a metadata object, although this is optional:
+
+```
+{"metadata": {
+    "version": "v3.0",
+    "vehicle_interface_id": "7ABF",
+    "vehicle": {
+        "make": "Ford",
+        "model": "Mustang",
+        "trim": "V6 Premium",
+        "year": 2013
+    },
+    "description": "highway drive to work",
+    "driver_name": "TJ Giuli",
+    "vehicle_id": "17N1039247929"
+}
+```
+
+The following lines are OpenXC messages with a `timestamp` field added, e.g.:
+
+    {"timestamp": 1385133351.285525, "name": "steering_wheel_angle", "value": 45}
+
+The timestamp is in [UNIX time](http://en.wikipedia.org/wiki/Unix_time)
+(i.e. seconds since the UNIX epoch, 00:00:00 UTC, 1/1/1970).
+
+## Official Signals
+
+These signal names are a part of the OpenXC specification, although some
+manufacturers may support custom message names.
+
+* steering_wheel_angle
+    * numerical, -600 to +600 degrees
+    * 10Hz
+* torque_at_transmission
+    * numerical, -500 to 1500 Nm
+    * 10Hz
+* engine_speed
+    * numerical, 0 to 16382 RPM
+    * 10Hz
+* vehicle_speed
+    * numerical, 0 to 655 km/h (this will be positive even if going in reverse
+      as it's not a velocity, although you can use the gear status to figure out
+      direction)
+    * 10Hz
+* accelerator_pedal_position
+    * percentage
+    * 10Hz
+* parking_brake_status
+    * boolean, (true == brake engaged)
+    * 1Hz, but sent immediately on change
+* brake_pedal_status
+    * boolean (True == pedal pressed)
+    * 1Hz, but sent immediately on change
+* transmission_gear_position
+    * states: first, second, third, fourth, fifth, sixth, seventh, eighth,
+      ninth, tenth, reverse, neutral
+    * 1Hz, but sent immediately on change
+* gear_lever_position
+    * states: neutral, park, reverse, drive, sport, low, first, second, third,
+      fourth, fifth, sixth, seventh, eighth, ninth, tenth
+    * 1Hz, but sent immediately on change
+* odometer
+    * Numerical, km
+        0 to 16777214.000 km, with about .2m resolution
+    * 10Hz
+* ignition_status
+    * states: off, accessory, run, start
+    * 1Hz, but sent immediately on change
+* fuel_level
+    * percentage
+    * 2Hz
+* fuel_consumed_since_restart
+    * numerical, 0 - 4294967295.0 L (this goes to 0 every time the vehicle
+      restarts, like a trip meter)
+    * 10Hz
+* door_status
+    * Value is State: driver, passenger, rear_left, rear_right.
+    * Event is boolean: true == ajar
+    * 1Hz, but sent immediately on change
+* headlamp_status
+    * boolean, true is on
+    * 1Hz, but sent immediately on change
+* high_beam_status
+    * boolean, true is on
+    * 1Hz, but sent immediately on change
+* windshield_wiper_status
+    * boolean, true is on
+    * 1Hz, but sent immediately on change
+* latitude
+    * numerical, -89.0 to 89.0 degrees with standard GPS accuracy
+    * 1Hz
+* longitude
+    * numerical, -179.0 to 179.0 degrees with standard GPS accuracy
+    * 1Hz
+
+License
+=======
+
+Copyright (c) 2012-2013 Ford Motor Company
+
+Licensed under the BSD license.
+
+[OpenXC]: http://openxcplatform.com