SNLS638A December 2018 – August 2019 DP83825I
Near-End Loopback provides the ability to loop the transmitted data back to the receiver through the digital or analog circuitry. The point at which the signal is looped back is selected using loopback control bits[3:0] in the BISCR register. Auto-Negotiation should be disabled before selecting the Near-End Loopback modes. This constraint does not apply for external-loopback mode.