SPRUII0F May 2019 – June 2024 TMS320F28384D , TMS320F28384D-Q1 , TMS320F28384S , TMS320F28384S-Q1 , TMS320F28386D , TMS320F28386D-Q1 , TMS320F28386S , TMS320F28386S-Q1 , TMS320F28388D , TMS320F28388S
For each VLAN Tag Filter, the application has the following comparison options:
For example, if a filter is enabled for 16-bit comparison, SVLAN Type, and Outer VLAN Tag, any single or double VLAN Tagged frames with Outer SVLAN Tags are compared with this filter, and a pass or fail result is obtained.
The application can enable both Perfect and Hash Filtering. The overall VLAN Filter Result is based on the Perfect Filter result and the Hash Filter result (if enabled). The filter result is passed to the application as part of the status bits.
Perfect filtering is done based on the MAC_VLAN_Tag_Filter registers. For each VLAN Tag Filter, the MAC compares the relevant VLAN Tag ID and gives a result. If any one of the VLAN Tag Filters gives a match, then the frame is considered to have passed the VLAN Tag Filters. If the frame mismatches all the filters, then the frame is considered to have failed the VLAN filter. This behavior is applicable only when the Inverse Filtering is not enabled in MAC_VLAN_Tag_Ctrl Register.
If inverse Filtering is enabled and the frame has mismatched all the relevant filters, then the frame is considered to have passed the VLAN filter. If the frame matches any one of the relevant filters, then the frame is considered as a fail. If none of the enabled filters can perform a comparison or if none of the filters are enabled, then the frame is bypassed to the application.
The overall filter result and the programming on the VTFE and RA bits of the MAC Filter Register determine if the frame is dropped or forwarded to the application. If RA = 1 or VTFE = 0, it does not matter if the filter result is a pass or fail. The frame is always forwarded. If RA = 0 and VTFE = 1, only then, if the VLAN Tag Filter result is a pass does the MAC forward the frame. If the frame is forwarded to the application, then the relevant filter result is indicated through the Status bits.