Image Processing Reference
In-Depth Information
communication jobs is aligned with the communication schedule, in LIN the schedule of the LIN
InterfacemodulegovernsthecommunicationscheduleontheLINbus.IncontrasttothisinCAN,the
temporal schedule of the PDU transmission is governed by the
Com
module (see below). In FlexRay,
each communication job can consist of one or more “communication operations,” each of these com-
munication operations handling exactly one communication frame (including the PDUs contained
in this frame).
The interface modules are designed to be able to deal with multiple different drivers for differ-
ent types of CCs (e.g., freescale's MFR or FlexRay CCs based on the BOSCH E-Ray core in
the FlexRay case). Furthermore, the Interface module wraps the API provided by the Transceiver
Driver module and provides support for multiple different Transceiver Driver modules (similar to
the support for multiple different Driver modules).
Transport protocol
(
xxTp
): he transport protocol is used to perform “segmentation and reassembly
of large PDUs.” On CAN (
CanTp
), this protocol is compatible (in certain configuration settings) to
ISO TP (see Section ..). Just like ISO TP, the user of the services provided by the transport protocol
is the diagnostic layer, called Diagnostic Communication Manager in AUTOSAR (see below).
Network management
(
xxNm
,
Nm
): Similar to OSEK NM (see Section ..), the AUTOSAR NM
modules provide means for the coordinated transition of the ECUs in a network into and out of a
low-power (or even power down) sleep mode. AUTOSAR NM is hereby divided into two modules:
a communication protocol-independent module named “
Generic NM
(
Nm
)” and communication
protocol-dependent modules named
FlexRay NM
(
FrNm
)and
CAN NM
(
CanNm
).
∗
State manager
(
xxSm
): he State Manager modules (
CanSm
,
LinSm
,and
FrSm
)facilitatethe“state
management of the respective CC” with respect to communication system-dependent start-up and
shutdown features and provide a common state machine API to the upper layer (i.e., the Commu-
nication Manager [
ComM
]). his API consists of functions for requesting the communication modes
Full
,
Silent
(i.e., listen only), and
No Communication
.
PDU router
(
PduR
): The PDU Router module provides two major services. On the one hand, it
“dispatches PDUs received via the underlying modules” (i.e., Interface and Transport Layer mod-
ules) to the different higher layers (
Com
,
Dcm
). On the other hand, the PDU router “performs
gateway functionalities” between different communication networks by forwarding PDUs from one
interface to another of either the same (e.g., FlexRay to FlexRay) or of different type (e.g., CAN
to FlexRay). Routing decisions in the PDU Router are based on a static routing table and on the
identifiers of the PDUs.
PDU multiplexer
(
IpduM
): he PDU Multiplexer module takes care of “multiplexing parts of a PDU.”
Hereby, the value of a dedicated part of the PDU (the “multiplexer switch”) is used to define the
semantic content of the remainder of the PDU (just like the tag element in a variant record or a
union in programming languages). In the reception case, multiplexed PDUs are forwarded from the
PduR
to the
IpduM
for demultiplexing. Once demultiplexed, the
IpduM
hands the PDUs back to
the
PduR
.Inthesendingcase,the
PduR
obtains a PDU from
Com
and hands this PDU to the
IpduM
for multiplexing. he
IpduM
returns the multiplexed PDU to the
PduR
, who routes the multiplexed
PDU to its final destination.
Communication
(
Com
): he
Com
module provides “signal-based communication” to the upper layer
(
Rte
). he signal-based communication service of
Com
can be used for intra-ECU communication
as well as for inter-ECU communication. In the former case,
Com
mainly uses shared memory for this
∗
AsLINisamaster-slavebus,no
LinNm
isrequired,astheLINmasterdictateswhenthenetworkshalltransitintoa
low-power mode.
