Image Processing Reference
In-Depth Information
Src
Addr
Addr
Type
Dst
Addr
PCI
Data
FIGURE .
ISOtransportlayer—frameformat.
The “protocol control information (PCI)” field is used to distinguish between the different frame
types (i.e., SF, FF, CF, FC). Furthermore, the PCI field carries the “total number of data bytes” to be
transmitted in case of a SF or an FF, a “sequence number” in case of a CF (to facilitate early detec-
tion of a loss of a CF), and more detailed information regarding the “type of flow control” in case
of an FC.
18.5.2 Diagnostics—KWP2000 (ISO/DIS 14230-3)/UDS (ISO/DIS 14229-1)
The KWP [] and the UDS [] define client/server diagnostic services, which allow a tester
device (client) to control diagnostic functions in an ECU (server) via a serial data link. Hereby, the
provided services, the encoding of the service identifiers (SID), and the encoding of the parame-
ters are standardized by the KWP and the UDS specification. For the exchange of information
between the client and the server (and vice versa), both diagnostic protocols use the previously
described transport layer. The services provided by KWP and UDS can be grouped into the
following six functional units:
Diagnostic management
: This functional unit covers all services realizing diagnostic management
functions between the client and the server. Examples for these kind of services are the services
startDiagnosticSession
for initiating a diagnostic session,
stopDiagnosticSession
for terminating a diagnostic session,
ecuReset
for resetting an ECU, and
readECUIdentifi-
cation
for reading ECU identification information like the serial number or the programming date
of the ECU.
Data transmission
: This functional unit covers all services dealing with data exchange between
the client and the server. Two prominent examples for these services are the services
readMemoryByAddress
and
writeMemoryByAddress
,whichareusedtoreadandwrite
a memory range (defined by start address and the number of bytes to read/write) of the ECU.
Stored data transmission
: his functional unit covers all services which are used to perform exchange
of data, which are stored within the ECU (in a nonvolatile way). Examples for these kind of services
are the service
readDiagnosticTroubleCodes
which is used to retrieve stored trouble codes
from the ECU's error log as well as the service
clearDiagnosticInformation
,whichisused
to remove all entries from the ECU's error log.
I/O control
: This functional unit covers all services which deal with input and output control
functions. An example for a service contained in this group is the service
inputOutputControl
ByLocalIdentifier
,whichcanbeusedbytheclienttosubstituteavalueforaninputsignalof
the server.
Remote activation of routine
: This functional unit covers all services which provide remote acti-
vation of routines within an ECU. Examples for services in this functional unit are the services
startRoutineByAddress
and
stopRoutineByAddress
,whichareusedtoremotely
invoke a routine in the server (ECU) and to terminate an executing routine in the server (ECU).
Hereby, the routine to invoke or stop is identified by the routine's address.
Upload/download
: This functional unit covers all services which realize upload/download
functionality between the client and the server. Examples for services within this unit are the
