SPRUIV7B May 2022 – September 2023 AM620-Q1 , AM623 , AM625 , AM625-Q1 , AM625SIP
When the device is set to boot through the Ethernet mode, the ROM Code configures the Ethernet module and the interface mode (RMII, RGMII) according the the BOOTMODE pin settings, see Section 5.4.5, Ethernet Boot Device Configuration. Also consult the boot parameter table for the Ethernet boot, see Section 5.6.7, Ethernet Boot Parameter Table.
When Link Info = 0, the link parameters are read using MDIO scan. This is the typical setting when using an external PHY. With these parameters, the ROM identifies the PHY and establishes link with the supported speed and duplex mode.
When Link Info = 1, no MDIO scan is performed, and the link parameters are programmed by the ROM based on the RGMII status register. This is the typical setting when configured as a MAC to MAC RGMII interface whereby RGMII pins of two devices can be connected diretly and establish link in force mode. The chosen configuration will be Gigabit, full duplex mode.
Note that booting from RGMII requires that an attached PHY be configured for RGMII-ID Mode immediately upon exiting reset. The ROM will not make this configuration change to the PHY.
The ROM will setup RGMII mode enabling internal delay mode.