Transmitter Interface - 9.0 English

Tri-Mode Ethernet MAC LogiCORE IP Product Guide (PG051)
Document ID
PG051
Release Date
2023-11-07
Version
9.0 English

Transmit Interface AXI4-Stream Signal Pins defines the AXI4-Stream transmit signals of the core, which are used to transmit data from the user to the core. Transmit Interface Sideband Signal Pins defines transmit sideband signals. A detailed description of operation is provided in Transmitting Outbound Frames.

Table 1. Transmit Interface AXI4-Stream Signal Pins
Signal Direction Clock Domain Description
tx_axis_mac_tdata[7:0] In tx_mac_aclk Frame data to be transmitted.
tx_axis_mac_tvalid In tx_mac_aclk Control signal for tx_axis_mac_tdata port. Indicates the data is valid.
tx_axis_mac_tlast In tx_mac_aclk Control signal for tx_axis_mac_tdata port. Indicates the final transfer in a frame.
tx_axis_mac_tuser In tx_mac_aclk Control signal for tx_axis_mac_tdata port. Indicates an error condition, such as FIFO underrun, in the frame allowing the MAC to send an error to the PHY.
tx_axis_mac_tready Out tx_mac_aclk Handshaking signal. Asserted when the current data on tx_axis_mac_tdata has been accepted and tx_axis_mac_tvalid is High. At 10/100 Mbps, this is used to meter the data into the core at the correct rate.
  1. All signals are active-High.
Table 2. Transmit Interface Sideband Signal Pins
Signal Direction Clock Domain Description
tx_ifg_delay[7:0] In tx_mac_aclk Control signal for configurable interframe gap
tx_collision Out tx_mac_aclk Asserted by the Ethernet MAC core level to signal a collision on the medium and that any transmission in progress should be aborted. Always 0 when the Ethernet MAC core level is in full-duplex mode.
tx_retransmit Out tx_mac_aclk When asserted at the same time as the tx_collision signal, this signals the client to resupply the aborted frame to the Ethernet MAC core level for retransmission. Always 0 when the Ethernet MAC core level is in full-duplex mode.
tx_statisitics_vector[31:0] 2 Out tx_mac_aclk A statistics vector that gives information on the last frame transmitted.
tx_statistics_valid Out tx_mac_aclk Asserted at end of frame transmission, indicating that the tx_statistics_vector is valid.
  1. All signals are active-High.
  2. When PFC is enabled tx_statistics_vector has a bus width of [32:0].

The following table defines the optional AXI4-Stream AV transmit signals included when the AVB functionality is selected.

Table 3. Transmit Interface AXI4-Stream AV Signal Pins
Signal Direction Clock Domain Description
tx_axis_av_tdata[7:0] In tx_mac_aclk Frame data to be transmitted.
tx_axis_av_tvalid In tx_mac_aclk Control signal for tx_axis_av_tdata port. Indicates the data is valid.
tx_axis_av_tlast In tx_mac_aclk Control signal for tx_axis_av_tdata port. Indicates the final transfer in a frame.
tx_axis_av_tuser In tx_mac_aclk Control signal for tx_axis_av_tdata port. Indicates an error condition, such as FIFO underrun, in the frame allowing the MAC to send an error to the PHY.
tx_axis_av_tready Out tx_mac_aclk Handshaking signal. Asserted when the current data on tx_axis_av_tdata has been accepted and tx_axis_av_tvalid is High. At 100 Mbps, this is used to meter the data into the core at the correct rate.
  1. All signals are active-High.

The statistics for the frame transmitted are contained within the tx_statistics_vector output. The bit field definition for the Vector is defined in the following table.

Table 4. Bit Definition for the Transmitter Statistics Vector
emacclient txstats Name Description
32 PFC_FRAME_TRANSMITTED Extra vector bit included when the PFC functionality is included. This indicates that the Ethernet MAC has generated and transmitted a PFC frame.
31 PAUSE_FRAME_TRANSMITTED Asserted if the previous frame was a pause frame that the MAC itself initiated in response to a pause_req assertion.
30 BYTE_VALID Asserted if a MAC frame byte (DA to FCS inclusive) is in the process of being transmitted. This is valid on every clock cycle.

Do not use this as an enable signal to indicate that data is present on (R)(G)MII_TXD.
29 Reserved Returns logic 0.
28:25 TX_ATTEMPTS[3:0] The number of attempts that have been made to transmit the previous frame. This is a 4-bit number: 0 should be interpreted as 1 attempt; 1 as 2 attempts, up until 15 as 16 attempts.
24 Reserved Returns logic 0.
23 EXCESSIVE_COLLISION Asserted if a collision has been detected on each of the last 16 attempts to transmit the previous frame.
22 LATE_COLLISION Asserted if a late collision occurred during frame transmission.
21 EXCESSIVE_DEFERRAL Asserted if the previous frame was deferred for an excessive amount of time as defined by the constant “maxDeferTime” in IEEE 802.3-2008.
20 TX_DEFERRED Asserted if transmission of the frame was deferred.
19 VLAN_FRAME Asserted if the previous frame contained a VLAN identifier in the length/type field when transmitter VLAN operation is enabled.
18:5 FRAME_LENGTH_COUNT The length of the previous frame in number of bytes. The count stays at 16368 for any jumbo frames larger than this value.
4 CONTROL_FRAME Asserted if the previous frame had the special MAC Control Type code 88-08 in the length/type field.
3 UNDERRUN_FRAME Asserted if the previous frame contained an underrun error.
2 MULTICAST_FRAME Asserted if the previous frame contained a multicast address in the destination address field.
1 BROADCAST_FRAME Asserted if the previous frame contained a broadcast address in the destination address field.
0 SUCCESSFUL_FRAME Asserted if the previous frame was transmitted without error.