How to filter CAN messages in Autosar?

Question

I am new to AUTOSAR com module. I would like to perform some scenario to check specific messages in CAN FD. Here I want to block all the CAN FD messages except one message (eg: ID: 0x22) during some event occurred.

My idea is to loop all the CAN FD PDU ID's and check the corresponding message ID(0x22). Here the problem is, I have to traverse through all the CAN FD PDU ID's. (If CAN FD PDU's are 200, I have to loop 200 times.)

I would like to know, Is there any other good method to block all the CAN FD message except some messages in AUTOSAR environment? Also where i have to block this PDU's ? Is it in COM module or CANIf module ? Please correct me if my understandings are wrong.

Answer 1

You can try to create several Tx ISignalIPduGroups in the SystemDescription/EcuExtract. You assign each ISignalIpdu to the according ISignalIPduGroup. Then you can enable/disable the necessary ISignalIPduGroup.

e.g.

IPduGroup_Tx_A - CommunicationDirection=OUT
    ISignalIPdu_Tx1
    ISignalIPdu_Tx2
IPduGroup_Tx_B - CommunicationDirection=OUT
    ISignalIPdu_Tx3
    ISignalIPdu_Tx4

IPduGroup_Rx_B - CommunicationDirection=IN
    ISignalIPdu_Rx1
    ISignalIPdu_Rx2
IPduGroup_Rx_B - CommunicationDirection=IN
    ISignalIPdu_Rx3
    ISignalIPdu_Rx4

You can either trigger it directly over Com

void MyCdd_MainFunction(void)
{
    if (cond_tx_a == TRUE) {
        Com_IpduGroupStart(COM_IPDUGROUP_TX_A, TRUE);
    } else {
        Com_IpduGroupStop(COM_IPDUGROUP_TX_A);
    }
    if (cond_tx_b == TRUE) {
        Com_IPduGroupStart(COM_IPDUGROUP_TX_B, TRUE);
    } else {
        Com_IpduGroupStop(COM_IPDUGROUP_TX_B);
    }
    
    if (cond_rx_a == TRUE) {
        Com_IpduGroupStart(COM_IPDUGROUP_RX_A, TRUE);
    } else {
        Com_IpduGroupStop(COM_IPDUGROUP_RX_A);
    }
    if (cond_rx_b == TRUE) {
        Com_IPduGroupStart(COM_IPDUGROUP_RX_B, TRUE);
    } else {
        Com_IpduGroupStop(COM_IPDUGROUP_RX_B);
    }
}

So, when cond_tx_a == TRUE it will start the IPduGroup_TX_A and therefore, the ISignalIPdu_Tx1 and ISignalIPdu_Tx2 will be transmitted now, but ISignalIPdu_Tx1 and ISignalIPdu_Tx2 will not be sent, unless cond_tx_b == TRUE. The same is happening with the IPduGroup_RX_A and IPduGroup_RX_B and their mapped ISignalIPdus, except, for Rx PDUs, you actually disable to the reception, but actually the Deadline Monitoring of Rx ISignalIPdus.

You could also configure such switching of IPduGroups in BswM (see configuration BswMPduGroupSwitch) without much writing direct code.

We had this with some OEM, where all messages had a assignment to a PowerSource, if transmitted or not.

IpduGroup_PowerSource_PlusB
IpduGroup_PowerSource_ACC
IPduGroup_PowerSource_IG1
IPduGroup_PowerSource_IG2

We had some rules generated out of the NetworkDescription, which automatically start/stop the Ipdus depending on, if they are mapped to the group or not. PowerStatus was the input to the BswM. BswM even has now BswMTimer support. So you could e.g. make rules, to:

• start a BswMTimer_IG1 with a timeout of 3000ms.
• after the BswMTImer_IG1 elapsed, that is another input to actually switch the Rx-IpduGroup on, in order to start the timeout monitoring in Com for the mapped PDUs only 3000ms after IG-ON. That is usually some settling time, where all the ECUs in the vehicle wakeup/start (Clamp15), and not all messages are all yet available on bus, and would cause Timeout DTCs to be logged.

The nice thing about BswM is, it is mostly configured, without actually writing one line of code manually. You could even update this in case of POSTBUILD configurations.