Mark whether a PID is present in response.

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

diff --git a/README.mkd b/README.mkd
index 5e962f0..0c28206 100644 (file)
--- a/README.mkd
+++ b/README.mkd
@@ -9,17 +9,6 @@ This library doesn't assume anything about the source of your diagnostic message
 requests or underlying interface to the CAN bus. It uses dependency injection to
 give you complete control.
 
-## OBD-II Basics
-
-TODO diagram out a request, response and error response
-
-* store the request arb id, mode, pid, and payload locally
-* send a can message
-* get all new can messages passed to it
-* Check the incoming can message to see if it matches one of the standard ECU
-  response IDs, or our arb ID + 0x8
-* if it matches, parse the diagnostic response and call the callback
-
 ## Usage
 
 First, create some shim functions to let this library use your lower level
@@ -28,7 +17,7 @@ system:
     // required, this must send a single CAN message with the given arbitration
     // ID (i.e. the CAN message ID) and data. The size will never be more than 8
     // bytes.
-    void send_can(const uint16_t arbitration_id, const uint8_t* data,
+    bool send_can(const uint16_t arbitration_id, const uint8_t* data,
             const uint8_t size) {
         ...
     }
@@ -48,8 +37,8 @@ With your shims in place, create a `DiagnosticShims` object to pass them around:
 
     DiagnosticShims shims = diagnostic_init_shims(debug, send_can, set_timer);
 
-With your shims in hand, send a simple PID request to the stadnard broadcast
-address, `0x7df`:
+With your shims in hand, send a simple PID request to the standard broadcast
+address, `0x7df` (we use the constant `OBD2_FUNCTIONAL_BROADCAST_ID` here):
 
     // Optional: This is your callback that will be called the response to your
     // diagnostic request is received.
@@ -59,7 +48,7 @@ address, `0x7df`:
 
     DiagnosticRequestHandle handle = diagnostic_request_pid(&shims,
             DIAGNOSTIC_STANDARD_PID, // this is a standard PID request, not an extended or enhanced one
-            0x7df, // the request is going out to the broadcast arbitration ID
+            OBD2_FUNCTIONAL_BROADCAST_ID, // the request is going out to the broadcast arbitration ID
             0x2, // we want PID 0x2
             response_received_handler); // our callback (optional, use NULL if you don't have one)
 
@@ -102,13 +91,13 @@ address, `0x7df`:
         }
     }
 
-## Requests for other modes
+### Requests for other modes
 
 If you want to do more besides PID requests on mode 0x1 and 0x22, there's a
 lower level API you can use. Here's how to make a mode 3 request to get DTCs.
 
     DiagnosticRequest request = {
-        arbitration_id: 0x7df,
+        arbitration_id: OBD2_FUNCTIONAL_BROADCAST_ID,
         mode: OBD2_MODE_EMISSIONS_DTC_REQUEST
     };
     DiagnosticRequestHandle handle = diagnostic_request(&SHIMS, &request, NULL);
@@ -156,6 +145,13 @@ lower level API you can use. Here's how to make a mode 3 request to get DTCs.
         }
     }
 
+## Dependencies
+
+This library requires 2 dependencies:
+
+* [isotp-c](https://github.com/openxc/isotp-c)
+* [bitfield-c](https://github.com/openxc/bitfield-c)
+
 ## Testing
 
 The library includes a test suite that uses the `check` C unit test library.
@@ -167,6 +163,18 @@ You can also see the test coverage if you have `lcov` installed and the
 
     $ BROWSER=google-chrome-stable make coverage
 
+## OBD-II Basics
+
+TODO diagram out a request, response and error response
+
+* store the request arb id, mode, pid, and payload locally
+* send a can message
+* get all new can messages passed to it
+* Check the incoming can message to see if it matches one of the standard ECU
+  response IDs, or our arb ID + 0x8
+* if it matches, parse the diagnostic response and call the callback
+
+
 ## Future Notes
 
 you're going to request a few PIDs over and over again at some frequency