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What is an MDIO interface?
Management Data Input/Output (MDIO), also known as Serial Management Interface (SMI) or Media Independent Interface Management (MIIM), is a serial bus defined for the Ethernet family of IEEE 802.3 standards for the Media Independent Interface, or MII. …
Is MDIO a I2C?
MDIO – A short history For most pluggable optical transceivers the interface used for monitor and control is the I2C interface. Defined as part of MII in IEEE802. MDIO works with 1.2V supply with a clock rate of 4MHz (downward compatibility to 100 kHz).
What does the word PHY?
adj. 1. of or relating to the body, as distinguished from the mind or spirit. 2. of, relating to, or resembling material things or nature: the physical universe.
What do you need to know about MDIO?
MDIO History. Management Data Input/Output, or MDIO, is a 2-wire serial bus that is used to manage PHYs or physical layer devices in media access controllers (MACs) in Gigabit Ethernet equipment. The management of these PHYs is based on the access and modification of their various registers.
How is the MDIO interface implemented in a Mac?
The MDIO interface is implemented by two signals: MDC clock: driven by the MAC device to the PHY. MDIO data: bidirectional, the PHY drives it to provide register data at the end of a read operation.
When does the MDIO signal need to be stable?
Further, MDIO has to remain stable 10 ns (hold time) after the rising edge of MDC. When the PHY drives the MDIO line, the PHY has to provide the MDIO signal between 0 and 300 ns after the rising edge of the clock.
What kind of resistor do I need for MDIO?
The MDIO requires a specific pull-up resistor of 1.5 kΩ to 10 kΩ, taking into account the total worst-case leakage current of 32 PHYs and one MAC. Before a register access, PHY devices generally require a preamble of 32 ones to be sent by the MAC on the MDIO line. The access consists of 16 control bits, followed by 16 data bits.