SNLS638A December 2018 – August 2019 DP83825I
When the DP83825I enters into Active Sleep mode, all internal circuitry shuts down in the PHY except for the SMI and energy detection circuitry on the TD± and RD± pins. In this mode, the DP83825 sends out NLPs every 1.4 seconds to wake up the link partner. Automatic power up occurs when a link partner is detected.
Active Sleep is enabled by setting bits[14:12] = 0b110 in the PHY Specific Control Register (PHYSCR, address 0x0011).