Using LAN8720 modules as Ethernet interface for custom LPC1768 mbed boards

Although the original LPC1768 mbed board is featuring a DP83848 chip, because there are available low cost (about $2.50) LAN8720 modules from various sellers I decided to give it a try. For more details about LAN8720 see the datasheet.

LAN8720 Ethernet Physical Layer Transceiver module /media/uploads/hudakz/lan8720_.jpg

Unfortunately the RX_ER pin was not available at the module's connector. So I took a thin wire, soldering iron and connected it to the NC (Not Connected) pin.

/media/uploads/hudakz/la8720_rx_er02.jpg

LAN8720 module pinout

/media/uploads/hudakz/lan8720_pinout02.jpg

Wiring

LAN8720 moduleLPC1768 board
TX1<=>94
RX_ER<=>89
TX_EN<=>93
TX0<=>95
RX0<=>91
RX1<=>90
nINT/RETCLK<=>88
CRS<=>92
MDIO<=>86
MDC<=>87
GND<=>GND
VCC<=>+3.3V


MBED library modifications

No MBED library modifications are needed.

Tested with

TCPSocket_HelloWorld
mbed-os-example-sockets
WebSwitch_mbed-dev
WebSwitch_mbed-os


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