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Use LiteEth to add ethernet to an ECP5 with a PMOD #66
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Hi @cjearls, the easiest way through a PMOD would be a RMII interface. It seems this cheap module that is also used on Arduino/ESP2 projects could be used: https://www.waveshare.com/lan8720-eth-board.htm You would just have to rotate it by 180°. To use this with LiteX, you would just need to add an extension to your platform, for example for an SDCard: _sdcard_pmod_ios = [
("sdcard_pmoda", 0,
Subsignal("clk", Pins("pmoda:3")),
Subsignal("cmd", Pins("pmoda:1"), Misc("PULLMODE=UP")),
Subsignal("data", Pins("pmoda:2 pmoda:4 pmoda:5 pmoda:0"), Misc("PULLMODE=UP")),
Misc("SLEWRATE=FAST"),
IOStandard("LVCMOS33"),
)
]
self.platform.add_extension(_sdcard_pmod_ios) And define the IOs similarly to the other RMII PHYs (here from NeTV2): # RMII Ethernet
("eth_clocks", 0,
Subsignal("ref_clk", Pins("D17")),
IOStandard("LVCMOS33"),
),
("eth", 0,
Subsignal("rst_n", Pins("F16")),
Subsignal("rx_data", Pins("A20 B18")),
Subsignal("crs_dv", Pins("C20")),
Subsignal("tx_en", Pins("A19")),
Subsignal("tx_data", Pins("C18 C19")),
Subsignal("mdc", Pins("F14")),
Subsignal("mdio", Pins("F13")),
Subsignal("rx_er", Pins("B20")),
Subsignal("int_n", Pins("D21")),
IOStandard("LVCMOS33")
), Since the number of IOs is limited on the PMOD, some optional IOs will probably not be present (maybe And integrate it like this in your design: # Ethernet ---------------------------------------------------------------------------------
from liteeth.phy.rmii import LiteEthPHYRMII
self.submodules.ethphy = LiteEthPHYRMII(
clock_pads = self.platform.request("eth_clocks"),
pads = self.platform.request("eth"))
self.add_ethernet(phy=self.ethphy) |
@cjearls: This solution has been tested with a cheap LAN8720 module on an Arty S7 and just requires a minor modification to the LAN8720 module: Integrated in the LiteX SoC with the following code: # Ethernet ---------------------------------------------------------------------------------
# Add IOs to Board's platform.
from litex.build.generic_platform import Pins, Subsignal, IOStandard
def eth_lan8720_rmii_pmod_io(pmod):
# Lan8020 RMII PHY "PMOD": To be used as a PMOD, MDIO should be disconnected and TX1
# connected to PMOD8 IO.
return [
("eth_clocks", 0,
Subsignal("ref_clk", Pins(f"{pmod}:6")),
IOStandard("LVCMOS33"),
),
("eth", 0,
Subsignal("rx_data", Pins(f"{pmod}:5 {pmod}:1")),
Subsignal("crs_dv", Pins(f"{pmod}:2")),
Subsignal("tx_en", Pins(f"{pmod}:4")),
Subsignal("tx_data", Pins(f"{pmod}:0 {pmod}:7")),
IOStandard("LVCMOS33")
),
]
platform.add_extension(eth_lan8720_rmii_pmod_io("pmodb"))
# Create RMII Ethernet PHY.
from liteeth.phy.rmii import LiteEthPHYRMII
self.submodules.ethphy = LiteEthPHYRMII(
clock_pads = platform.request("eth_clocks"),
pads = platform.request("eth"),
refclk_cd = None)
# Add Ethernet MAC and connect it to the Soft-CPU.
#self.add_ethernet(phy=self.ethphy)
# Add Etherbone and connect if to the SoC.
self.add_etherbone(phy=self.ethphy) |
…to it. See enjoy-digital/liteeth#66 (comment) for the PMOD.
Hello,
I was wondering if LiteEth currently supports any PMODs, and if not, what the best way to add a LiteEth ethernet interface to an ECP5 with 25k LUTs that doesn't have an ethernet jack on the board would be.
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