An ENC28J60 (IC2) handles the network physical connection (PHY ... to generic references in the code library. For the SD card this is an SPI interface, and pins for chip select and card detect.

including an SD card interface, two UARTs, two I²C busses, SPI with two chip selects, I²S, twelve GPIOs with four capable of PWM, and a USB 2.0 OTG controller. There are also a pair of radio ...