The KSZMNX offers the industry-standard GMII/MII Media Independent Interface (GMII) is compliant to the IEEE Specification. Dave Fifield [email protected] GMII Electrical Specification IEEE Interim Meeting, San Diego, January N. Interface) for connection to GMII/MII MACs in Gigabit . Clarified power cycling specification to have all supply voltages to the KSZMNX.

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Transmit error may be raised for one or more clock periods during frame transmission to request the PHY to deliberately corrupt the frame in some visible way that precludes it from being received as valid.

Media-independent interface

Received clock signal recovered from incoming received data. It is not to be confused with RM2. If a collision is detected, COL also goes high while the collision persists.

TTL signal levels are used for 5 V or 3. Source-synchronous clocking is used: Retrieved from ” https: There is no signal which defines whether the interface is in full or half duplex mode, but both the MAC and the PHY need to agree. Ethernet family of local area network technologies. However, at 1 ns edge rates a trace longer than about 2. There are 32 addresses, each containing 16 bits. This means a slight modification of the definition of CRS: Four things were changed compared to the MII standard to achieve this:.

Views Read Edit View history. At power up, using autonegotiationthe PHY usually adapts to whatever it is connected to unless settings are altered via the MDIO interface. The management interface controls the behavior of the PHY. The receive clock is recovered from the incoming signal during frame reception. The original MII transfers network data using 4-bit nibbles in each direction 4 transmit data bits, 4 receive data bits.


Reference clock may be an input on both devices from an external clock source, or may be driven from the MAC to the PHY. It contains a bitmask with the following meaning: Being media independent means that different types of PHY devices for connecting to different media i.

The standard MII features a small set of registers: Typically used for on-chip connections; in chip-to-chip usage mostly replaced by XAUI. By using this site, you agree to the Terms of Use and Privacy Policy.

This requires the PCB to be designed to add a 1.

Archived from the original on This page was last edited on 19 Novemberat At gmi the standard says the signals need not be treated as transmission lines. The receiver clock is much simpler, with only one clock, which is recovered from the incoming data.

Media-independent interface – Wikipedia

On the other hand, newer devices may support 2. The RMII signals are treated as lumped signals rather than transmission lines; no termination or controlled impedance is necessary; output drive and thus slew rates need to be as slow as possible rise times from 1—5 ns to permit this. Input high threshold is 2. The media-independent interface MII was originally defined as a standard interface to specjfication a Fast Ethernet i. Current revisions of IEEE This interface requires 9 signals, versus MII’s The transmit enable signal gmmii held high during frame transmission and low when the transmitter is idle.

The original MII design has been extended to support reduced signals and increased speeds.

Retrieved 20 April From Wikipedia, the free encyclopedia. For this reason, the reduced media independent interface was developed. This arrangement allows the MAC to operate without having to be aware of speciifcation link speed. More recently, raising transmit error outside frame transmission is used to indicate the transmit data lines are being used for special-purpose signalling.


Transmit and receive path each use one differential pair for data and another differential pair for clock. Carrier sense is high when transmitting, receiving, or the medium is otherwise sensed as being in use. When no clock can be recovered i. Zpecification should be able to drive 25 pF of capacitance which allows for PCB traces up to 0. Given trends in the semiconductor industry and the fact that both ICs are usually on the same board, lack of 5 V tolerance is probably very common, and chips that actually drive 5 V are probably even rarer.

Ethernet Computer buses Serial buses. These registers can be used to configure the device say “only gigabit, full duplex”, or “only full duplex” or can be used to determine the current operating mode.

This may be used to abort a frame when some problem is detected after transmission has already started.

The specification states that inputs should be 5 V tolerant, however, some popular chips with RMII interfaces are not 5 V tolerant. The first 16 addresses have a defined usage, [7] while the others are device specific.

Some of the preamble nibbles may be lost.

Data is sampled on the rising edge only i. For receive, two data values are defined: As such it consists of a preamble, start frame delimiter, Ethernet headers, protocol specific data and a cyclic redundancy check CRC. The MAC may omit the signal if it has no use for this functionality, in which case the signal should be tied low for the PHY.