Visible to Intel only — GUID: nik1411172604208
Ixiasoft
Visible to Intel only — GUID: nik1411172604208
Ixiasoft
3.2.2.3. Low Latency 40-100GbE IP Core TX Data Bus Without Adapters (Custom Streaming Interface)
When no adapters are used, the LL 40GbE custom interface bus width is 2 words (128 bits) and the LL 100GbE custom interface bus width is 4 words (256 bits). The LL 40GbE custom interface operates at 312.5 MHz and the LL 100GbE custom interface operates at 390.625 MHz.
Signal Name |
Direction |
Description |
---|---|---|
din[<w>*64-1:0] | Input |
Data bytes to send in big-endian mode. Most significant 64-bit word is in the higher-order bits. In 40GbE variations, the most significant word is in bits [127:64] and in 100GbE variations, the most significant word is in bits [255:192]. The Low Latency 40-100GbE IP core does not process incoming frames of less than nine bytes correctly. You must ensure such frames do not reach the TX client interface. |
din_sop[<w>-1:0] | Input |
Start of packet (SOP) location in the TX data bus. Only the most significant byte of each 64‑bit word may be a start of packet. Bit 63 or 127 are possible for the 40GbE and bits 255, 191, 127, or 63 are possible for 100 GbE. Bit 0 of din_sop corresponds to the data word in din[63:0]. |
din_eop[<w>-1:0] | Input |
End of packet location in the TX data bus. Indicates the 64-bit word that holds the end-of-packet byte. Any byte may be the last byte in a packet. Bit 0 of din_eop corresponds to the data word in din[63:0]. |
din_eop_empty[<w>*3-1:0] | Input |
Indicates the number of empty (invalid) bytes in the end-of-packet byte in the word indicated by din_eop. If din_eop[z] has the value of 0, then the value of din_eop_empty[(z+2):z] does not matter. However, if din_eop[z] has the value of 1, then you must set the value of din_eop_empty[(z+2):z] to the number of empty (invalid) bytes in the end-of-packet word z. For example, if you have a 100GbE IP core and want to indicate that in the current clk_txmac clock cycle, byte 6 in word 2 of din is an end-of-packet byte, and no other words hold an end-of-packet byte in the current clock cycle, you must set the value of din_eop to 4'b0100 and the value of din_eop_empty to 12'b000_110_000_000. |
din_idle[<w>-1:0] | Input |
Indicates the words in din that hold Idle bytes or control information rather than Ethernet data. One-hot encoded. |
din_req |
Output |
Indicates that input data was accepted by the IP core. |
tx_error[<w>-1:0] | Input | When asserted in an EOP cycle (while din_eop[<w>-1:0] is non-zero), directs the IP core to insert an error in the corresponding packet before sending it on the Ethernet link. This signal is a test and debug feature. In loopback mode, the IP core recognizes the packet upon return as a malformed packet. |
clk_txmac | Output |
TX MAC clock. The clock frequency should be 312.5 MHz in LL 40GbE IP cores, and 390.625 MHz in LL 100GbE IP cores. The clk_txmac clock and the clk_rxmac clock (which clocks the RX datapath) are assumed to have the same frequency. |
The IP core reads the bytes in big endian order. A packet may start in the most significant byte of any word. A packet may end on any byte.