The Raspberry Pi microcontroller itself does not have an Ethernet MAC, but it can be easily implemented through the programmable IO of the Raspberry Pi. The programmable PIO of the Raspberry Pi microcontroller that costs 5 yuan a piece is indeed a miracle, with IO below 250MHz. Control everything.
The SA636DK evaluation demonstration board is used to evaluate the RF development platform for 110.592 MHz RF and 9.8 MHz IF.
Filter circuit (various design solutions + schematic diagram)
51 microcontroller to RTL8019 Ethernet control example (original program + schematic diagram).