Systems, methods, and apparatuses including a Physical layer (PHY) block coupled to a Media Access Control layer (MAC) block via a PHY/MAC interface. Each of the PHY and MAC blocks include a plurality of Physical Interface for PCI Express (PIPE) registers. The PHY/MAC interface includes a low pin count PIPE interface comprising a small set of wires coupled between the PHY block and the MAC block. The MAC block is configured to multiplex command, address, and data over the low pin count PIPE interface to access the plurality of PHY PIPE registers, and the PHY block is configured to multiplex command, address, and data over the low pin count PIPE interface to access the plurality of MAC PIPE registers. The PHY block may also be selectively configurable to implement a PIPE architecture to operate in a PIPE mode and a serialization and deserialization (SERDES) architecture to operate in a SERDES mode.