AXI4-Stream Control and Status Ports - TX - 4.1 English

10G/25G High Speed Ethernet Subsystem Product Guide (PG210)

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4.1 English
Table 1. AXI4-Stream Interface - TX Path Control/Status Signals
Name I/O Clock Domain Description
ctl_tx_enable I clk

TX Enable.

When sampled as a 1, this signal is used to enable the transmission of data.

When sampled as a 0, only IDLEs are transmitted by the core.

This input should not be set to 1 until the receiver it is sending data to is fully synchronized and ready to receive data. (that is, the receiver on the link partner is not sending a remote fault condition.) Otherwise, loss of data can occur. If this signal is set to 0 while a packet is being transmitted, the current packet transmission is completed and then the core stops transmitting any more packets.

ctl_tx_custom_preamble_enable I clk When asserted, this signal enables the use of tx_preamblein as a custom preamble instead of inserting a standard preamble.
tx_preamblein[55:0] I clk This is the custom preamble which is a separate input port rather than being in-line with the data. It should be valid during the start of the packet.
ctl_tx_ipg_value[3:0] I clk

The ctl_tx_ipg_value defines the target average minimum Inter Packet Gap (IPG, in bytes) inserted between packets. Typical value is 12. The ctl_tx_ipg_value can also be programmed to a value in the 0 to 7 range, but in that case, it is interpreted as meaning "minimal IPG", so only Terminate code word IPG is inserted; no Idles are ever added in that case and that produces an average IPG of around four bytes when random-size packets are transmitted.

This signal can be optionally present.

ctl_tx_fcs_ins_enable I clk

Enable FCS insertion by the TX core.

If set to 0, the core does not add FCS to the packet.

If set to 1, the core calculates and adds FCS to the packet.

This input cannot be dynamically changed between packets

ctl_tx_send_lfi I clk Transmit Local Fault Indication (LFI) code word. Takes precedence over Remote Fault Indication (RFI).
ctl_tx_send_rfi Input clk

Transmit Remote Fault Indication (RFI) code word.

If sampled as a 1, the TX path transmits only RFI code words.

This input should be set to 1 until the RX path is fully synchronized and is ready to accept data from the link partner.

ctl_tx_send_idle I clk

Transmit IDLE code words.

If sampled as a 1, the TX path only transmits IDLE code words.

This input should be set to 1 when the partner is sending RFI code words.

ctl_tx_ignore_fcs I clk

Enable FCS error checking at the AXI4-Stream interface by the TX core. This input only has effect when ctl_tx_fcs_ins_enable is Low.

If set to 0 and a packet with bad FCS is being transmitted, it is not binned as good.

If set to 1, a packet with bad FCS is binned as good.

The error is flagged on the signals stat_tx_bad_fcs and stomped_fcs and the packet is transmitted as it was received.

Note: Statistics are reported as if there was no FCS error.
ctl_tx_parity_err_response I clk Parity error response by the TX Core. If this bit is set to 0, the core does not take any action if any parity errors are detected. If this bit is set to 1, the core stomps the outgoing FCS (i.e., bit-wise inverse) and asserts stat_tx_bad_fcs.