SNLA404 December 2022 DP83TC811R-Q1 , DP83TC811S-Q1 , DP83TC812R-Q1 , DP83TC812S-Q1 , DP83TG720R-Q1 , DP83TG720S-Q1
The microcontroller checks the PHY ID to confirm the MCU is communicating with the appropriate device. This is done by reading registers 0x2 and 0x3 to check the vendor and specific PHY ID. Reading correct values can indicate the PHY has been powered up correctly and communication via SMI has been established.