SNLA431 January 2024 DP83TC812R-Q1 , DP83TC812S-Q1
The INH signal (pin 10) gives an indication if the device is in sleep mode or not. This pin is Hi-Z when the PHY is in TC-10 SLEEP and pulled low by external pull resistor. This pin is driven high for all other PHY states. In sleep mode, the device appears non-functional and register access is not available. Make sure this pin is equal to Vsleep voltage to be sure the device is not in sleep mode.