hi, i want to implement ethernet communication between two stm32 boards without using phy, but only gpio's connected by jumpers. how can i disable the phy?

Hello everyone, i want to send ethernet packet from one stm32h745 nucleo board to another board. i connect the boards with rj45 biderictional cable, and i use the eth in both boards(one to transmit and one to transmit). i try to debug the program of ...