Low Latency Ethernet 10G MAC IP Design Example User Guide: Agilex™ 3 and Agilex™ 5 FPGAs and SoCs

ID 813665
Date 8/04/2025
Public
Document Table of Contents

2.3.3. Reset Scheme

Upon power-up, reset the design example (i_rst_n, i_tx_rst_n, and i_rx_rst_n) and wait for o_rst_ack_n, o_tx_rst_ack_n, and o_rx_rst_ack_n signals to get asserted to de-assert the resets. Asserting these signals resets all channels and their components.

Reset sequencing logic handles the resets to MAC and PHY by considering the input i_rst_n, i_tx_rst_n, and i_rx_rst_n as well as tx_ready and rx_ready status signals from PHY.

The PHY should be on reset before dynamic reconfiguration switching.

Figure 11. Reset Scheme for 10M/100M/1G/2.5G MGBASE Ethernet Design Example
Reset controls for the design can be done through the In-System Sources and Probes (ISSP) provided in the example design with reset inputs mapped as below:
Bit ISSP
0 i_rx_rst_n
1 i_tx_rst_n
2 i_rst_n
3 reconfig_reset
Table 7.  Reset Signals Port Mapping
Reset Signal Name Description for MAC Description for PHY
i_rst_n Global reset for MAC. Reset sequencing logic adds certain logic to the reset and connects to MAC with with port mapping as "csr_rst_n". Global reset for PHY with port mapping i_rst_n.
i_tx_rst_n TX directional reset for MAC. Reset sequencing logic adds certain logic to the reset and connects to MAC with port mapping as "tx_rst_n". TX directional reset for PHY with port mapping i_tx_rst_n.
i_rx_rst_n RX directional reset for MAC. Reset sequencing logic adds certain logic to the reset and connects to MAC with port mapping as "rx_rst_n". RX directional reset for PHY with port mapping i_rx_rst_n.
reconfig_reset Reset the entire reconfiguration clock domain, including the soft registers (CSR). Port is mapped to reconfig_reset.