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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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. Four things were changed compared to the MII standard to achieve this:. At least the standard says the signals need not be treated as transmission lines. Drivers should be able to drive 25 pF of capacitance which allows for PCB traces up to 0.

The transmit enable signal is held high during frame transmission and low when the transmitter is idle. Some of the preamble nibbles may be lost.

The first 16 addresses have a defined usage, [7] while the others are device specific. Source-synchronous clocking is used: Input high threshold is 2. When no clock can be recovered i.

Media-independent interface – Wikipedia

For receive, two data values are defined: More recently, raising transmit error outside frame transmission is used to indicate the transmit data lines are being used for special-purpose signalling. Retrieved 20 April This page was last edited on 19 Novemberat These registers can be used to configure the device say “only gigabit, full duplex”, or “only full duplex” or can be used to determine gjii current operating mode.


The g,ii MII transfers network data using 4-bit nibbles in each direction 4 transmit data bits, 4 receive data bits. TTL signal levels are used for 5 V or 3. On the other hand, newer devices may support 2. This means a slight modification of the definition of CRS: By using this site, you agree to the Terms of Use and Privacy Policy.

This arrangement allows the MAC to operate without having to be aware of the link speed. Ethernet Computer buses Serial buses. As such it consists specufication a preamble, start frame delimiter, Ethernet headers, protocol specific data and a cyclic redundancy check CRC. Reference clock may be an input on both devices from an external clock source, or may be driven from the MAC to the PHY. The media-independent interface MII was originally defined as a standard interface to connect a Fast Ethernet i.

Transmit and receive path each use one differential pair for data and another differential pair for clock.

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. However, at 1 ns edge rates a trace longer than about 2. Retrieved from ” https: From Wikipedia, the specifictaion encyclopedia.

This may be used to abort a frame when some problem is detected after transmission has already started. The receiver clock is much simpler, with only one clock, which is recovered from the incoming data. Views Read Edit View history. If a collision is detected, Tmii also goes high while the collision persists. It specificwtion a bitmask with the following meaning: 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.


Typically used for on-chip connections; in chip-to-chip usage mostly replaced by XAUI. 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. This interface requires 9 signals, versus MII’s Received clock signal recovered from incoming received data.

Media-independent interface

The receive clock is recovered from the incoming signal during frame reception. The specification states that inputs should be 5 V tolerant, however, some popular chips with RMII interfaces are not 5 V tolerant.

There are 32 addresses, each containing 16 bits. Data is sampled on the rising edge only i. It is not to be confused with RM2. At power up, using autonegotiationthe PHY usually adapts to whatever it is connected to unless settings are altered via the MDIO interface. 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.

The management interface controls the behavior of the PHY. Current revisions of IEEE Archived from the original on Carrier sense is high when transmitting, receiving, or the medium is otherwise sensed as being in use. Being media independent means that different types of PHY devices for connecting to different media i. For this reason, the reduced gmi independent interface was developed.

Ethernet family of local spefification network technologies. This requires the PCB to be designed to add a 1.