Image Processing Reference
In-Depth Information
requestDownload service, which gives the client the possibility to request the negotiation of
adatatransferfromclienttoserver,the requestUpload service, which gives the client the pos-
sibility to request the negotiation of a data transfer from server to client, and the transferData
service, which actually takes care of the data transmission between client and server.
In KWP as well as in UDS, services are identified by the SID field, which is the first byte in
adiagnosticmessage. Based on this field, the layout of the remainder of the diagnostic message is
completely diferent. he diagnostic server uses the SID to select the proper service requested by the
client and interprets the remainder of the diagnostic message as parameters to the service request
according to the SID.
Describing the format of the diagnostic messages for each value of SID is beyond the scope of this
chapter. Detailed information on this topic can be obtained from the respective ISO specifications
[,].
18.6 ASAM
The Association for Standardization of Automation and Measuring Systems (ASAM) started as an
initiative of German car manufacturers with the goal to define standards for data models, interfaces,
and syntax specifications for testing, evaluation, and simulation applications.
Apart from several data exchange formats like open diagnostic data exchange format (ODX),
the functional specification exchange format (FSX), the meta data exchange format for software
module sharing (MDX), and the fieldbus exchange format (FIBEX), ASAM defines the universal
measurement and calibration protocol family (XCP), which is described in the next section.
18.6.1 XCP—The Universal Measurement and Calibration
Protocol Family
heuniversalmeasurementandcalibrationprotocolfamily(XCP)[]isusedforthefollowingmain
purposes:
Synchronous data transfer (acquisition and stimulation)
Online calibration
Flash programming for development purposes
Prior to describing these main operations of XCP though, we will focus on the protocol's inter-
nal structure. XCP itself consists of two main parts, namely, the “XCP protocol layer” and several
“XCP transport layers,” one dedicated transport layer for each underlying communication protocol
(currently CAN, FlexRay, USB, TCP/IP, UDP/IP, and SxI are supported). Figure . illustrates this
XCP protocol stack.
XCP
CAN
FlexRay
TCP/IP
UDP/IP
USB
Sxl
FIGURE .
XCP protocol stack.
∗This diagnostic message is payload from ISO TP's point of view.
 
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