SPRUJ53B April 2024 – September 2024 TMS320F28P550SJ , TMS320F28P559SJ-Q1
The FSI receiver core has the capability of generating an interrupt when the received data or ping frame's tag matches the reference tag in RX_FRAME_TAG_CMP or RX_PING_TAG_CMP, respectively.
Each tag compare register allows the user to not only select a reference tag (TAG_REF) but also set up a mask (TAG_MASK) to ignore specified bits in the reference tag. For tag matching to be enabled, the CMP_EN bit must be set. When the tag compare is enabled and a successful match occurs, the PING_TAG_MATCH, the DATA_TAG_MATCH or the ERROR_TAG_MATCH in RX_EVT_ERR_STATUS is set. The corresponding match register status can be cleared by writing to RX_EVT_ERR_CLEAR. Also, if required to set the match register status in software, the user must do so by writing to the RX_EVT_ERR_SET register.
The tag matching scheme is not a filtering scheme. Tag matching is only a notification scheme to alert the user when a specific tag is detected in a data or ping frame. Both RX_INTR_EVT_CTRL_1 and RX_INTR_EVT_CTRL_2 interrupts can be set up to generate an interrupt when a tag match event occurs.
Another feature used when tag matching is enabled is the broadcast feature. The broadcast feature can be enabled by setting the BRDCST_EN in RX_FRAME_TAG_CMP or RX_PING_TAG_CMP. When broadcast mode is enabled, the third bit of the tag is treated as a broadcast bit. If the received tag has a third bit set, then the tag is treated as a match regardless of the other tag bit comparisons. Note that a match caused by TAG_REF and TAG_MASK is also considered a match.
Note that the tag matching scheme is not a filtering scheme. For example, if tag matching is enabled and a frame is received with a non-matching tag, the frame is still saved in the buffer and the corresponding event status bits (FRAME_DONE, DATA_FRAME_RCVD) is set.
Tag matching is required in multi-peripheral TDM configurations as described in Section 25.3.11; however, tag matching can also be used in single-peripheral configurations as needed.