SPRUIM2H May 2020 – October 2023 AM2431 , AM2432 , AM2434 , AM6411 , AM6412 , AM6421 , AM6422 , AM6441 , AM6442
When MII_RT_TXCFG0/1[9] PRE_TX_AUTO_SEQUENCEn is set to 1h (where n = 0 or 1), the data frame is passed from the RX L1 FIFO to TX L1 FIFO without any interaction of the PRU. This mode of operations is shown in Figure 6-257. The RX L1 FIFO will push data into TX L1 FIFO as long as it is enabled and not full.
There is no PRU dependency in this mode and no option for the PRU to perform any operation to the TX L1 FIFO. RX_RESET clears all data and status elements.
For ESC protocols, software should enable [6]RX_AUTO_FWD_PRE0/1 and [4]RX_L2_EN0/1 bits in MII_RT_RXCFG0/1 registers.
For non ESC protocols, software can enable MII_RT_TXCFG0/1[1] TX_AUTO_PREAMBLEn and MII_RT_RXCFG0/1[2] RX_CUT_PREAMBLEn bit (where n = 0 or 1) to insure full preamble is generated for each TX frame.
The PRU core can read the passing through frame by polling the standard R31 register. In Direct mode, the PRU R31 Command is ignored and disabled, except for TX_RESET and RX_RESET.
The following are the legal configurations supported for Direct Connection: