CX11656 HomePlug 1.0 PHY Data Sheet
3.1.3.3
3.1.3.4
OP (Operation Code)
READ is indicated by “10”. WRITE is indicated by “01”.
PHYAD (PHY Address)
The PHY Address is 5 bits, allowing up the 32 unique PHY addresses. The CX11656 will
respond to PHY addresses indicated by 0bXX000. The “XX” bits of the PHY address are
controlled by the CX11656 interface pins MDI_ADRSEL(0:1). This allows the designer
to assign the CX11656 to one of 4 unique PHY addresses.
3.1.3.5
3.1.3.6
REGAD (Register Address)
The Register Address is 5 bits and is used to index the maximum of 32 individual
registers in the MDI address space. The CX11656 only implements the two mandated
MII registers. 0b00000 will index the MII Control Register and 0b00001 will index the
MII Status Register.
TA (Turnaround)
The turnaround time is a 2-bit time spacing between the Register Address field and the
Data field to avoid contention during a read transaction.
For reads, both the external host and the CX11656 remain three-stated for the first bit
time. The CX11656 will drive a “0” during the second bit time.
For writes, the external host drives a “1” for the first bit time and a “0” bit for the second
bit time.
3.1.3.7
Data
The data field is 16 bits. The first data bit transmitted and received is bit 15 of the register
being addressed.
102069A
Conexant Proprietary and Confidential Information
3-11
CONEXANT [ CONEXANT SYSTEMS, INC ]
