The document summarizes the Autosar CAN communication stack, which includes modules like COM, PDU-Router, CANIF, CANTP, CANSM, and CAN driver. It describes the interaction between these modules to transition from no communication to full communication state upon a request, transmit a message onto the CAN bus, and receive an incoming message from the CAN bus.

1. CAN STACK

2. OVERVIEW
• AUTOSAR CAN Stack
• Overview.
• Included modules.
• From COMM_NO_COMMUNICATION to COMM_FULL_COMMUNICATION.
• Transmission request.
• Receive indication.

3. AUTOSAR CAN STACK:
OVERVIEW
Autosar VFB
• The integration of functions from different suppliers is established through a virtual
functional bus.
• Allow virtual integration between SW-c as long as communication mechanism is defined.
• Collection of all communication mechanism.
• Interfaces on an abstract level that allow s/w design regardless the target h/w.
RTE
• Realization of VFB for a specific ECU.
• It mange the communication inter/intra ECU.

4. AUTOSAR CAN STACK:
OVERVIEW
Communication Stack for CAN
• COM:
- Transfer signals from, and to RTE.
- Pass signals to CANTP or PDUR
depending on the used service.
• PDU-Router:
- Route I-PDUs between the following
modules: Communication interface (CANIF),
Transport protocol (CANTP), Diagnostics (DCM)

5. AUTOSAR CAN STACK:
OVERVIEW
Communication Stack for CAN
• CANIF:
- It abstracts the interface regardless
Location of the driver (internal/external).
• CANTP:
- Segment and reassemble data
Longer than 8 bytes.
• CAN Driver:
Abstraction for the CAN controller hardware.

6. AUTOSAR CAN STACK:
OVERVIEW
Communication Stack for CAN
• CANSM:
Change communication mode
as requested.
• CANTRCV:
Control external CAN transceiver
hardware, It observe the bus and provide
physical network diagnostics.

7. AUTOSAR CAN STACK:
OVERVIEW
Included modules from service layer:
• ComM: Propagate requested communication mode to CanSM
• BSWM: Forward user requests to ComM and report
communication state to the user.
• ECUM: Detect passive wake up and initialize related modules.

8. AUTOSAR CAN STACK:
INCLUDED MODULES

9. Active VS Passive Wake-up
• Active wake-up: when the current ECU is the source of the
wake-up signal (sensor).
• Passive wake-up: when another ECU is the source of the
wake-up signal. In this case the ECU should receive NM
frames to keep the ECU in the passive wake-up mode.
AUTOSAR CAN STACK: FROM
COMM_NO_COMMUNICATION TO
COMM_FULL_COMMUNICATION

10. Modules interaction
1. For active wake-up User request communication mode.
2. ComM propagate requested mode to CANSM.
3. CANSM change the current mode to the requested mode by
calling CANIF APIs.
4. CANIF contact the CAN driver which write values in the CAN
controller register to go the requested communication mode.
5. The CAN controller send mode indication signal to upper
modules till it is back to ComM.
AUTOSAR CAN STACK: FROM
COMM_NO_COMMUNICATION TO
COMM_FULL_COMMUNICATION

11. 6- ComM notifies the BSWM to manage what will happen next to
start data transmitting.
AUTOSAR CAN STACK: FROM
COMM_NO_COMMUNICATION TO
COMM_FULL_COMMUNICATION
SWC1 RTE COMM CANSM CANIF CAN
Controller Controller
Red arrows indicate request direction
Blue arrows indicate confirmation messages direction

12. AUTOSAR CAN STACK: FROM
COMM_NO_COMMUNICATION TO
COMM_FULL_COMMUNICATION
APIs and State transitions:
COMM CANSM CANIF CAN Hardware
(controller)
Start State COMM_NO_COMMUN
ICATION
S_RNOCO:
S_CAN_TRCV_NORM
AL
CANIF_CS_INIT:
CANIF_CS_STO
PPED
CAN_READY STOP/SLEEP
Called APIs CanSM_RequestCom
Mode(NetworkHandle,
ComM_Mode:=COMM
_FULL_COMMUNICA
TION)
CanIf_SetControllerMo
de(CanSMControllerId,
CANIF_CS_STARTED
)
AND
CanIf_SetPduMode(Ca
nSMControllerId,
CANIF_SET_ONLINE)
Can_SetController
Mode (Controller,
CAN_T_STARTE
D).
request CAN
controller mode
transition to
START()
Callback fn. Configurable
confirmation to BswM.
ComM_BusSM_ModeI
ndication(Channel,Co
mMode:
=COMM_FULL_COM
MUNICATION)
CanSM_Controller
ModeIndication(ui
nt8,
COMM_FULL_CO
MMUNICATION)
CanIf_ControllerMo
deIndication
End State COMM_FULL_COMM
UNICATION
S_FUCO:
S_NO_BUS_OFF
CANIF_CS_INIT:
CANIF_CS_STAR
TED
CAN_READY START

13. AUTOSAR CAN STACK: FROM
COMM_NO_COMMUNICATION TO
COMM_FULL_COMMUNICATION
Modules state machine:
ComM CANSM CANIF CAN

14. Modules interaction
1. When BSWM receive confirmation signal that the channel is
ready it notifies the COM to take the massage from the RTE.
2. COM propagate the IPDU to PDUR which in turn forward the
message to the corresponding interface of TP modules (in our
case if the message is loner than 8 bytes will be forwarded to
CANTP else to CANIF).
3. CANIF sends data to the CAN driver which writes data in the
CAN controller registers.
4. After successful transmission TxConfirmation signal is sent
to upper layers.
AUTOSAR CAN STACK:
TRANSMISSION REQUEST

15. Modules interaction
SWC1 RTE COM PDUR CANIF CAN
Controller Controller
Red arrows indicate request direction
Blue arrows indicate confirmation messages direction
AUTOSAR CAN STACK:
TRANSMISSION REQUEST

16. AUTOSAR CAN STACK:
TRANSMISSION REQUEST
COM PduR CANIF CAN Hardware
(controller)
Called APIs PduR_ComTrans
mit
CanIf_Transmit Can_write Copy LPDU to
harware
Callback fn. Rte_COMCbkTAc
k_signalX()
Com_TxConfirmati
on
PduR_CanTxConfi
rmation
CanIf_CanTxCon
firmation
Tx interrupt
APIs and State transitions:

17. Modules interaction
To detect received data Interrupt or polling can be used
Interrupt: The controller will notify CANIF when data is received
Polling: CANIF will periodically check weather data is received or
not.
For both modes after the CANIF detects that there is received
data it will notify upper modules to read data.
After reaching the COM the received data will be available to be
called by the RTE when required.
AUTOSAR CAN STACK:
RECEIVE INDICATION

18. AUTOSAR CAN STACK:
RECEIVE INDICATION
COM PduR CANIF CAN Hardware
(controller)
Callback fn. Rte_COMCbk_sign
alX()
Com_RxIndication PduR_<module>Rx
Indication
CanIf_RxIndication Receive
Interrupt()
Called APIs CanIf_ReadRxNotif
Status()
CanIf_ReadRxPdu
Data
Read data from
CANIF Rx
buffer()
APIs and State transitions: