Visible to Intel only — GUID: lbl1457116875382
Ixiasoft
Visible to Intel only — GUID: lbl1457116875382
Ixiasoft
6.1. TX MAC Interface to User Logic
Signal |
Direction |
Description |
---|---|---|
clk_txmac | Output | Clock for the TX logic. Derived from pll_refclk, and is an output from the 25G Ethernet Intel FPGA IP core. clk_txmac is guaranteed to be stable when tx_lanes_stable is asserted. The frequency of this clock is 390.625 MHz. All TX MAC interface signals are synchronous to clk_txmac . |
l1_tx_data[63:0] | Input | Data input to MAC. Bit 63 is the MSB and bit 0 is the LSB. Bytes are read in the usual left to right order. The 25G Ethernet Intel FPGA 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. You must send each TX data packet without intermediate idle cycles. Therefore, you must ensure your application can provide the data for a single packet in consecutive clock cycles. If data might not be available otherwise, you must buffer the data in your design and wait to assert l1_tx_startofpacket when you are assured the packet data to send on l1_tx_data[63:0] is available or will be available on time. If readyLatency = 0, ensure that no data transition at the l1_tx_data bus at the same clock cycle l1_tx_ready is deasserted. You can transition the data at the l1_tx_data bus at the same clock cycle l1_tx_ready is asserted. If readyLatency = 3, ensure that no data transition at the l1_tx_data bus at the third clock cycle after l1_tx_ready is deasserted. You can transition the data at the l1_tx_data bus at the third clock cycles after l1_tx_ready is asserted. |
l1_tx_valid | Input | When asserted, indicates valid data is available on l1_tx_data[63:0]. You must assert this signal continuously between the assertions of l1_tx_startofpacket and l1_tx_endofpacket for the same packet regardless of the l1_tx_ready status. |
l1_tx_startofpacket | Input | When asserted, indicates the first byte of a frame. When l1_tx_startofpacket is asserted, the MSB of l1_tx_data drives the start of packet. Packets that drive l1_tx_startofpacket and l1_tx_endofpacket in the same cycle are ignored. |
l1_tx_endofpacket | Input | When asserted, indicates the end of a packet. Packets that drive l1_tx_startofpacket and l1_tx_endofpacket in the same cycle are ignored. |
l1_tx_empty[2:0] | Input | Specifies the number of empty bytes on l1_tx_data when l1_tx_endofpacket is asserted. |
l1_tx_error | Input | When asserted in the same cycle as l1_tx_endofpacket, indicates the current packet should be treated as an error packet. Assertion at any other position in the packet is ignored. The TX statistics counters do not reflect errors the IP core creates in response to this signal. |
l1_tx_ready | Output | When asserted, indicates that the MAC can accept the data. When the readyLatency = 0, the IP core accepts valid data in the same clock cycle in which it asserts l1_tx_ready. When the readyLatency = 3, the IP core accepts valid data 3 clock cycles after it asserts l1_tx_ready. |
l1_txstatus_valid | Output | When asserted, indicates that l1_txstatus_data[39:0] is driving valid data. |
l1_txstatus_data[39:0] | Output | Specifies information about the transmit frame. The following fields are defined:
|
l1_txstatus_error[6:0] | Output | Specifies the error type in the transmit frame. The following fields are defined:
|
pause_insert_tx0[FCQN-1:0] pause_insert_tx1[FCQN-1:0] |
Input | Available if you specify Pause or PFC. Indicates to the MAC if an XON, XOFF, Pause or PFC frame should be sent. FCQN equals 1 for Pause and 1-8 for PFC. In 1-bit programming mode, the IP core ignores pause_insert_tx1[FCQN-1:0]. In 2-bit programming mode, the higher-order bit is in pause_insert_tx1[FCQN-1:0] and the lower-order bit is in pause_insert_tx0[FCQN-1:0]. The following encodings are defined for 1-bit programming mode:
The following encodings are defined for the 2-bit programming model:
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