Management data input/output (MDIO), also known as serial management interface (SMI) is a serial busdefined for the Ethernet family of IEEE 802.3 standards for the media independent interface (MII). The CoreMDIO_APB is an MDIO controller that provides the set of registers to implement the procedures for controlling the MDIO transactions. The CoreMDIO_APB provides the standard APB target interface to configure the registers required for MDIO read or write transactions. The CoreMDIO_APB allows for MDC prescaler and also provides busy status information for the user or host application. CoreMDIO_APB has two functional blocks: Registers and Controller.