SPRUIM2H May 2020 – October 2023 AM2431 , AM2432 , AM2434 , AM6411 , AM6412 , AM6421 , AM6422 , AM6441 , AM6442
On the MII transmit ports, there is a multiplexer for each MII transmit port that enables selection of either the transmit data from the PRUs or from the RX MII interface of the other MII interface. Figure 6-259 shows a simple diagram of PRU transmit multiplexer.
The transmit multiplexers enable the PRU_ICSSG to either operate in a bypass mode where the PRU is not involved in processing MII traffic or use of one of the PRU cores for transmitting data into the MII interface. There are two instances of the TX MII multiplexer and the select lines for each TX multiplexer are provided by the PRU_ICSSG programmable registers (MII_RT_TXCFG0/1[8] TX_MUX_SELn, where n = 0 or 1). The select lines are common between register and FIFO interface. It is expected that the select lines will not change during the course of a frame so that can avoid data exchange error.