Project

Proposal

My project for digital system design this semester is to first, establish basic communications with a separate computer through the use of the RJ-45 port on the Nexys A7 board. Once this objective is completed, I will attempt to establish a base "web server" on the FPGA board to display or transfer information. This web server will not be using any pre-built application on other platforms such as Apache, Django, or Node.JS. Instead, I will try to focus on building out the networking back-end that will be required to communicate with other computers through the Ethernet port. Key elements that I will try to implement when going about this project are basic network naming protocols such as an IP address and MAC address, basic network data transfer protocols such as TCP/UDP, SCTP, ARP, and NTP protocols to name a few. Using these protocols as well as the IP, I will attempt to transfer packets of data in between the computer and FPGA.

Documentation

Defining constrain file for this project:

• This project will use the Clock Signal and SMSC Ethernet PHY ports from the master constrain file on GitHub. (Figure 1)

## Clock signal

set_property -dict { PACKAGE_PIN E3    IOSTANDARD LVCMOS33 } [get_ports { CLK50MHZ }]; #IO_L12P_T1_MRCC_35 Sch=clk100mhz

create_clock -add -name sys_clk_pin -period 10.00 -waveform {0 5} [get_ports {CLK50MHZ}];

## SMSC Ethernet PHY

set_property -dict { PACKAGE_PIN C9    IOSTANDARD LVCMOS33 } [get_ports { ETH_MDC }]; #IO_L11P_T1_SRCC_16 Sch=eth_mdc

set_property -dict { PACKAGE_PIN A9    IOSTANDARD LVCMOS33 } [get_ports { ETH_MDIO }]; #IO_L14N_T2_SRCC_16 Sch=eth_mdio

set_property -dict { PACKAGE_PIN B3    IOSTANDARD LVCMOS33 } [get_ports { ETH_RSTN }]; #IO_L10P_T1_AD15P_35 Sch=eth_rstn

set_property -dict { PACKAGE_PIN D9    IOSTANDARD LVCMOS33 } [get_ports { ETH_CRSDV }]; #IO_L6N_T0_VREF_16 Sch=eth_crsdv

set_property -dict { PACKAGE_PIN C10   IOSTANDARD LVCMOS33 } [get_ports { ETH_RXERR }]; #IO_L13N_T2_MRCC_16 Sch=eth_rxerr

set_property -dict { PACKAGE_PIN C11   IOSTANDARD LVCMOS33 } [get_ports { ETH_RXD }]; #IO_L13P_T2_MRCC_16 Sch=eth_rxd[0]

set_property -dict { PACKAGE_PIN D10   IOSTANDARD LVCMOS33 } [get_ports { ETH_RXD }]; #IO_L19N_T3_VREF_16 Sch=eth_rxd[1]

set_property -dict { PACKAGE_PIN B9    IOSTANDARD LVCMOS33 } [get_ports { ETH_TXEN }]; #IO_L11N_T1_SRCC_16 Sch=eth_txen

set_property -dict { PACKAGE_PIN A10   IOSTANDARD LVCMOS33 } [get_ports { ETH_TXD }]; #IO_L14P_T2_SRCC_16 Sch=eth_txd[0]

set_property -dict { PACKAGE_PIN A8    IOSTANDARD LVCMOS33 } [get_ports { ETH_TXD }]; #IO_L12N_T1_MRCC_16 Sch=eth_txd[1]

set_property -dict { PACKAGE_PIN D5    IOSTANDARD LVCMOS33 } [get_ports { ETH_REFCLK }]; #IO_L11P_T1_SRCC_35 Sch=eth_refclk

set_property -dict { PACKAGE_PIN B8    IOSTANDARD LVCMOS33 } [get_ports { ETH_INTN }]; #IO_L12P_T1_MRCC_16 Sch=eth_intn

• "Two on-board LEDs (LD23 = LED2, LD24 = LED1) connected to the PHY provide link status and data activity feedback." - Nexys A7 Reference Manual
• "The SMSC PHY uses the RMII interface"; This is a standard of Ethernet port pin-out
• "A 50 MHz clock needs to be generated for the mii_to_rmii core and the CLKIN pin of the external PHY"
• The constrain file already gives the specified RMII transmit signals, so the user only then needs to implement the signals into the architecture and initialize the connection. (Figure 2)
• Since the Ethernet module on the clock requires a clock input, I used the "clk_wiz_0.vhd" and the "clk_wiz_0_clk_wiz.vhd" file created by Xilinx to initiate the clock

Sources

• Microblaze Server Tutorial for Ethernet
• Sending Ethernet Traffic from FPGA to Computer
• Nexys 4 DDR Implementation Example
• NIC100 Ethernet Pmod
• Nexys A7 Ethernet Clock Discussion
• Media Independent Interface Wikipedia
• TCP/IP Stack FPGA Discussion
• LAN8720A/LAN8720Ai Reference Manual for Ethernet Pmod
• RMII Documentation

Ideas

• Working with RJ-45 Ethernet connector on the board for basic communication
  • Create Web Server potentially
    • "A web server is server software, or hardware dedicated to running this software, that can satisfy client requests on the World Wide Web. A web server can, in general, contain one or more websites. A web server processes incoming network requests over HTTP and several other related protocols." - Wikipedia
    • Probably will not have the time to implement this.