RP 1210D - Windows(TM) Communication API: Terminology
The following table describes the terminology used in this specification:
| Abbreviation | Description |
|---|---|
| API | Application Programmer's Interface. A documented methodology for programming application programs such that they operate cooperatively with other programs. Software programmers write applications that conform to one or many APIs. The RP1210 specification is considered an API. |
| Application (Single/Multi) | An executable process (or set of related processes/threads) that have issued one or more connections to the vehicle databus(es) using RP1210_ClientConnect (
).
RP1210 has always had a requirement to support at least 16 "clients". The intent of these "clients" was to support multiple connections from one application or a single vendor's suite of cooperating applications (Single-Application). RP1210 was not intended to support arbitrary simultaneous connections from multiple vendors' applications at the same time (Multi-Application). RP1210 in no way intends to require Multiple Applications running simultaneously. This is not practical for the software developer or the VDA vendor. |
| Automatic Bit Rate Detection/Auto Baud Detection | Brought to this document with the implementation of J1939-14 (J1939@500k), automatic bit rate detection (also called Auto Baud Detection) allows an application to connect to a databus that is running at any commonly defined speed forthat protocol. Therefore, the application does not have to try connecting serially to the databus at each speed supported by that VDA for that protocol and worry about causing databus errors (i.e. CAN error frames). See J1939-13 which defines the F, G pins of the HD diagnostic connector and J1939-14 which defines the J1939 protocol running at 500k. |
| Big Endian (MSB) or Motorola Format Integers | Also referred to in the document as the "most significant byte (MSB) first format." A format for representing integral bytes of data, conventionally used in Motorola microprocessors, where the bytes are numbered from left to right. (The Intel format, called Little Endian, numbers the bytes from right to left. See Little Endian.) |
| MSB/Motorola 2-Byle Integer Format |
|---|
| Byte 0 Byte 1 |
| MSB/Motorola 4-Byte Integer Format | |||
|---|---|---|---|
| Byte 0 | Byte 1 | Byte 2 | Byte 3 |
| Client | A "logical" connection to an onboard vehicle databus provided through a VDA via a call to RP1210_ClientConnect ( ). AVDA driver must support 16 clients connected through their VDA at one time. If a VDA supports multiple applications (see Application), these clients can be from these different applications. |
| DLL | Dynamic Link Library. A DLL is an implementation of an API and is a mechanism to link applications to libraries at run-time instead of at compile-time. The libraries are separate files and are not copied into an application's executable as with static linking. These libraries are called dynamic-link libraries (DLL) to emphasize that they are linked to an application when it is loaded and executed, rather than when linked. |
| ECM | Electronic Control Module. Synonymous with ECU. Sometimes mistakenly referred to as Engine Control Module, which is also categorized as an ECM/ECU. |
| ECU | Electronic Control Unit. The electronic control that will be communicated with (e.g.. engine, brakes, transmission). This term is used throughout this document. You will see the term TCM/TCU, BCM/BCU for transmission and body controllers as well as other flavors of xCM/xCU. They are all categorized as "generic" ECU/ECM's. |
| Event-driven Architecture | An operating system architecture that revolves around a messaging scheme governed by system events (a mouse click, a keyboard press are all examples of events). When an application receives an event directed to it, either from the operating system or another application or driver, it executes the code associated with that event. Windows™ architecture is modeled on this paradigm. |
| INI | Initialization file. This file contains information about every VDA vendors' API, such as protocols supported, communications ports supported, etc. See the section on INI files for the layout of the INI files used by the API. |
| Interface box | A legacy term used to refer to hardware components that translate between the RS-485J1708 vehicle datalink and an RS-232 serial port on a PC or other device. These are sometimes called "dumb boxes," as they do nothing but signal shifting. Most new interface boxes are no longer "dumb boxes", but specialty devices called VDA's (see VDA). However, some still lump VDA into the category of "interface boxes." |
| Interface Cable [or Cable) | Alternate term for RP 1210 Vehicle Diagnostic Adapter (VDA). Many RP 1210 end-users (including engineers) sometimes call RP 1210 VDAs "cables" or "interface cables." |
| Little Endian (LSB) or Intel Format Integers | Least significant byte first format. A format for representing integral bytes of data, conventionally used in Inte microprocessors, where the bytes are numbered from right to left. (The Motorola format, called Big Endian, numbers bytes from left to right. See Big Endian.) |
| LSB/lntel 2-Byle Integer Format | |
|---|---|
| Byte 1 | Byte 0 |
| LSB/lntel 4-Byte Integer Format | |||
|---|---|---|---|
| Byte 3 | Byte 2 | Byte 1 | Byte 0 |
| Multitasking operating system | An operating system that allows multiple processes to execute at a given time. Such an operating system divides its time and resources between the different running processes. Typically, time-slicing makes it difficult to do dedicated real-time processing with such systems. Windows™ is an example of such an operating system. |
| Network Protocol | A documented standard for network communications. Examples of network protocol standards in the automotive industry: SAE J1587, J1708, J1939, J1850, ISO15765; CAN (Controller Area Network) |
| Real-time Processing/Communication | Computation that requires operations to be performed at a high speed (often of the order of milliseconds) and, at times, in an unconditionally prioritized manner. This kind of processing is typical of PC to vehicle datalink communications. |
| RP1210 | Specification allowing 16 client connections from one application. This is referred to as Single Application (see Application). |
| RP1210 Multi-Application | Specification allowing 16 client connections from up to 16 different applications. This is referred to as Multi-Application and is covered in the Multi-Application Addendum. |
| RS-232 | A term usually used in reference to the communication ports available on most PCs. Formally defined as the "Recommended Standard" 232 in the ANSI (American National Standard Institution) specification as "the interface between data terminal equipment and data circuit-terminating equipment employing serial binary data interchange." |
| RS-485 | A term used in reference to a communication (COM) port available on some PCs. Formally, "Recommended Standard" 485 in the ANSI specification that defines a transmission scheme. This standard is widely utilized in the trucking industry for interfacing with the vehicle datalink. |
| TCP/IP | Transport Control Protocol/Internet Protocol. Some vehicle adapters allow connecting to a vehicle using this methodology. |
| USB | Universal Serial Bus. A high-speed serial bus coming into prevalence in the PC to peripheral intercommunications market. |
| VC I | Vehicle Communications Interface. Another term for VDA (see VDA). This term is more common in the automotive world. |
| VDA | Vehicle Datalink Adapter. The physical device, when connected to the vehicle databus, provides translation between the databus and that vendor's API. In RP 1210D, a VDA is referred to as a device implementing this specification. |
| Windows™ | A registered trademark (™) of the Microsoft Corporation. This term will refer to operating systems that will be supported under this RP. Non-Windows operating system support is covered in the "Non Windows Cross Platform Addendum". |