TCP/IP implementation as general I/O on 8bit avr?

Question

Atmel AVR

Is it at least theoretically possible? I think it’s possible, but I don’t know if there are any timings in the standards that MK can’t pull

Answer 1

Such an implementation already exists - for the ENC28J60 network controller, which has only receive and transmit buffers. There are no hard timings in the standard - everything can be set in timeout. Ultimately, only the speed of information exchange and the memory needed to process sockets and send hardware packets (SYN, ACK) will suffer.
But if you meant the implementation of Ethernet 10/100Mbit (mk outputs directly to the transformer) - then the answer is no AVR will not pull even 10 Mbit and it cannot work directly with differential pairs in hardware.