Packet Generation - 2.4 English - PG169

As mentioned earlier interlaken_0_pkt_gen is responsible for the generation of packets. Typically packet generator waits for the GT to get locked and Interlaken RX to get aligned. After alignment, the packet generator generates a predefined number of packets. The finite state machine (FSM) description of each state follows, and the state transition that occurs during this process is shown in the following figure.

TOP_IDLE_STATE

By default the controller will be in this state. When reset_done signal becomes active-High, it moves to GT_LOCK_STATE.

GT_LOCK_STATE

Sets the following:

• ctl_tx_enable = 1’b0
• ctl_tx_mubits = 8’d0
• ctl_tx_diagword_lanestat = 12'hFFF
• ctl_tx_diagword_intfstat = 1'b1
• init_done = 1'b0

and moves to WAIT_RX_ALIGN_STATE.

WAIT_RX_ALIGN_STATE

Waits for the Interlaken core stat_rx_aligned or simplex_mode_rx_aligned in simplex TX mode, which indicates that the ILKN RX core is aligned. After that, FSM moves to ENABLE_PKT_TRANS_STATE state.

ENABLE_PKT_TRANS_STATE

Sets the ctl_tx_enable = 1’b1 and moves to PKT_TX_INIT_STATE.

PKT_TX_INIT_STATE

Initialize all signals to start LBUS packet generation. When init_done and tx_rdyout is set, move to TRANSMIT_STATE_0.

TRANSMIT_STATE_0

Checks for the number of packets to be generated, and generates predefined size of LBUS packets.

• Moves to TRANSMIT_STATE_1 after sending respective SOP and EOP, and other LBUS control signals using the send_packet function.
• After sending all the packets, the FSM moves to the DONE_STATE.
• During transmission of the packets if ready = 0, the FSM controller moves to HOLD_STATE.

TRANSMIT_STATE_1

Sends remaining LBUS packet.

• Once pkt_end reached, FSM moves to TRANSMIT_STATE_0 to end the current LBUS packet and start new packet.
• During transmission of the packets if ready = 0, FSM controller moves to HOLD_STATE.

DONE_STATE

Sets tx_done_int = 1’b1 and moves to PKT_RESTART_STATE.

HOLD_STATE

If ready = 1, the FSM controller moves to TRANSMIT_STATE_0 or TRANSMIT_STATE_1 depending on which state it came from.

PKT_RESTART_STATE

Sets gen_busy = 0 and moves to TOP_IDLE_STATE.

In the Simple TX mode of operation because RX alignment information is not available, the state machine waits for you to input simplex_mode_rx_aligned. After you assert this input, the packet transmission starts.