SLUSBX9I March 2014 – July 2019 TPS23861
The TPS23861 operates as a fully automatic PSE in compliance with IEEE 802.3at when the AUTO bit is set as described in I2C Slave Address and AUTO Bit Programming section. Fully automatic operation means that the TPS23861 operates as a power-over-ethernet four-port PSE without any connection to a host system via the I2C bus. Generally speaking, when the bit is set, most specialized features of the TPS23861 are disabled.
The state of the AUTO bit is read only following power on, hardware reset (RESET pin) or writing a 1 to the RESAL bit in the Reset Register.
If the AUTO bit is set and the TPS23861 is connected to a host over the I2C bus, the host may change the register settings any time after power up, including changing operating mode. When the AUTO bit is set, the state of TPS23861 following power up is summarized below.
If a 250-mΩ resistor is used, the classification thresholds shifts slightly, but remains compliant with IEEE 802.3at.