Transmit Length Register (TLR) - 4.3 English

AXI4-Stream FIFO LogiCORE IP Product Guide (PG080)

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4.3 English

The Transmit Length Register shown in Store-and-Forward Mode and Cut-Through Mode. This register is used to store packet length values (the number of bytes in the packet) corresponding to valid packets ready for transmit. The data for the packet is stored in the transmit Data FIFO. The data is written to the AXI4-Stream FIFO core over the AXI4 interface, typically by a processor or DMA core such the Central DMA (CDMA). When presenting a transmit packet to the AXI4-Stream FIFO core, write the packet data to the Transmit Data FIFO first, then write the length of the packet into the TLR.

It is not valid to write data for multiple packets to the transmit data FIFO before writing the packet length values.