[AUTOSAR com 3. signal sending and receiving process tx/rx]

The theme of this series of articles is CAN Communications , It belongs to the communication function , Subdivide this function by module , Here's the picture 3 Shown . among CAN The core modules of communication are 4 individual ：COM modular ,PDU Router modular , CAN Interface Module and CAN Driver modular

From the whole Com From the perspective of communication structure, we can find ：

about CAN Driver Come on , The only interface to communicate with the upper module is CAN Interface module , Through this module, we can realize the well-known 3 individual ECU Communication function ：

CAN Communications , Through the interface layer to PDU Router modular ;（ route ：CanDrv–CanIf–PduR–Com）
UDS service , Through the interface layer to CANTp modular ;（ route ：CanDrv–CanIf–CanTp–PduR–Dcm）
XCP service , Through the interface layer to XCP modular .（ route ：CanDrv–CanIf–XCP)

1.Can Reception

Review previous articles menghuyouyou： according to ISO 11898-1 According to the standard , CAN The receive function requires the use of notifications (Indication) service , So how based on AUTOSAR Architecture implementation ？ in general ,AUTOSAR Architecturally CAN The flow chart of receiving software implementation is shown in the figure below 4 Shown ：

BSW The scheduler periodically calls CAN Driver Modular Can_MainFunction_Read function ;

CAN Driver Modular Can_MainFunction_Read The function will access CanController( Hardware ) The register of , As described in the previous article, the arbitration register , Data register and data length register , And read the data of these registers

After data reading , At this time, continue to call CAN Interface Modular CanIf_RxIndication function , So the data from CAN Driver The module is passed to the upper layer CAN Interface modular ;

CAN Interface The module calls again PduR Modular PduR_RxIndication function , Send data to PduR modular ;

PduR The module is routed to Com modular , call Com_RxIndication function , Send data to Com modular ,Com The module will store the data in its cache , The supply layer software reads and uses .

In addition, according to ISO 11898-1 The standard describes the contents of this article and later , Here's the picture 5 Above the red line of . Aforementioned 4 Core modules , except CAN Driver Ability to access or configure hardware , Other modules cannot . They will be connected through the data protocol unit (PDU) Form to realize data transmission , These contents will be introduced in detail in the following article .

2.Can Sending of

CAN The sending function requires the use of a request (Request) Service and confirmation (Comfirmation) service ,AUTOSAR Architecturally CAN The sending function is shown in the figure below 6、7 Shown .

BSW The scheduler periodically calls Com Modular Com_MainFunction_Tx function ,Com The module will read the data to be sent from its buffer ;

Com Modular Com_MainFunction_Tx The function will call PduR Modular PduR_ComTransmit function , Send data to PduR modular ;

PduR The module is routed to CAN Interface modular , call CanIf_Transmit function , So the data from PduR The module is passed to the lower level CAN Interface modular ;

CAN Interface The module calls again Can Driver Modular Can_Write function , Write the data to the corresponding register ;

And CAN The receiving function is the same ,Can_Write Function will access the quorum , Data length and data register , Write data to .

chart 7 It describes the confirmation process after data transmission , namely ：

BSW The scheduler periodically calls CAN Driver Modular Can_MainFunction_Write function ;

CAN Driver Modular Can_MainFunction_Write The function will access CanController( Hardware ) Relevant register , Read relevant data for confirmation to the upper layer ;

After data reading , At this time, continue to call CAN Interface Modular CanIf_TxComfirmation function , So the data from CAN Driver The module is passed to the upper layer CAN Interface modular ;

CAN Interface The module calls again PduR Modular PduR_TxConfirmation function , Send data to PduR modular ;

PduR The module is routed to Com modular , call Com_TxConfirmation function , Confirm the sending status .