VCI - Virtual CAN Interface - Ixxat

Accessing the busAs the example shows, only individual IDs or groups of IDs can be activated withthe simple acceptance filter. However, if the required IDs do not correspond to acertain bit sample, the acceptance filter quickly reaches its limits. This is where thesecond filter stage with the ID list comes into play. Each list can contain up to2048 IDs, or 4096 entries.Individual IDs or groups of IDs can be added to the list via the function canControlAddFilterIdsand removed again with the function canControlRemFilterIds. Theparameters dwCode and dwMask have the same format as with the acceptancefilter.If the function canControlAddFilterIds is called, for example, with the values fromthe previous example, the function adds the IDs 100h to 103h to the list. If onlyone single ID is to be added when the function is called, the required ID (includingRTR-bit) is entered in dwCode and dwMask set to FFFh or 3FFFFFFFh.The acceptance filter can be completely blocked by calling the function canControlSetAccFilterif the value CAN_ACC_CODE_NONE is entered for dwCode andthe value CAN_ACC_MASK_NONE for dwMask. Further filtering thereafter is onlycarried out based on the ID list. Calling the function with the valuesCAN_ACC_CODE_ALL and CAN_ACC_MASK_ALL, on the other hand, opens theacceptance filter completely. The ID list therefore has no effect in this case.3.1.3 Message channelA message channel is generated or opened by calling the function canChannelOpen.The parameter fExclusive defines whether the connection is to be usedexclusively. If the value TRUE is entered here, no further message channels can beopened after the function has been successfully run. If the CAN connection is notused exclusively, any number of message channels can theoretically be created.In the case of exclusive use of the connection, the message channel is directlyconnected to the CAN controller. The following diagram shows this configuration.20Copyright IXXAT Automation GmbH C-API Programming Manual, Version 1.5