SNIP_CLASSIC_CANIF_SECTION_9_5_Transmit_confirmation_with_buffering

9.5 Transmit confirmation (with buffering) «module» CanIf «module» SchM «Peripheral» CanController «module» Can CanIf User alt Transmit Buffering [Buffer is filled] [Buffer is empty] <User_TxConfirmation>() Remove L-PDU successfully requested for transmission from transmit buffer() Write L-PDU into CAN Hardware() Transmit Confirmation Interrupt() Can_Write() check transmit buffers for other pending L-PDU() Can_Write(Std_ReturnType, Can_HwHandleType, const Can_PduType*) CanIf_TxConfirmation() <User_TxConfirmation>(PduIdType, Std_ReturnType) Write L-PDU into CAN Hardware() CanIf_TxConfirmation(PduIdType) Transmit Confirmation Interrupt() Figure 9.5: Transmit confirmation with buffering Activity Description Transmit interrupt Acknowledged CAN frame signals successful transmission to receiving CAN Controller and triggers transmit interrupt. Confirmation to CanIf CanDrv calls service CanIf_TxConfirmation(). Parameter CanTxPduId specifies the L-PDU previously transmitted by Can_Write(). CanDrv must store the all in HTHs pending L-PDU Ids in an array organized per HTH to avoid new search of the L-PDU ID for call of CanIf_TxConfirmation(). Check of transmit buffers The transmit buffers of CanIf checked, whether a pending L-PDU is stored or not. Transmit request passed to CanDrv In case of pending L-PDUs in the transmit buffers the highest priority order the latest L-PDU is requested for transmission by Can_Write(). It signals a successful L-PDU transmission to the upper layer. Thus Can_Write() can be called re-entrant. Remove transmitted L-PDU from transmit buffers The L-PDU pending for transmission is removed from the transmission buffers by CanIf. Confirmation to the upper layer Calling of the corresponding upper layer confirmation service <User_TxConfirmation>(id, E_OK). It signals a successful L-SDU transmission to the upper layer.