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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It is not to be confused with RM2. There are 32 addresses, each containing 16 bits. Some of the preamble nibbles may be lost.
Views Read Edit View history. The specification states that inputs should be 5 V tolerant, however, some popular chips with RMII interfaces are not spceification V tolerant.
The first 16 addresses have a defined usage,  while the others are device gmi. 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. 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.
Transmit and receive path each use one differential pair for data and another differential pair for clock. For this reason, the reduced media independent interface was developed.
Media-independent interface – Wikipedia
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 requires the PCB to be designed to add a 1.
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. From Wikipedia, the free encyclopedia.
On the other hand, newer devices may support 2. At least the standard says the signals need not be treated psecification transmission lines. Ethernet family of local area network technologies. This page was last edited on 19 Novemberat Specificztion signal levels are used for 5 V or 3.
Received clock signal recovered from incoming received data. Archived from the original on Typically used for on-chip connections; in chip-to-chip usage mostly replaced by XAUI. Four things were changed compared to the MII standard to achieve this:. Current revisions of IEEE Carrier sense is high when transmitting, receiving, or the medium is otherwise sensed as being in use. The transmit enable signal is held high during frame transmission and low when the transmitter is idle.
Retrieved 20 April Input high threshold is 2. As such it consists of a preamble, start frame delimiter, Ethernet headers, protocol specific data and a cyclic redundancy check CRC.
Being media independent means that different types of PHY devices for connecting to different media i. Source-synchronous clocking is used: If a collision is detected, COL also goes high while the collision persists.
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 specificqtion permit this.
Data is sampled on the rising edge only i. Retrieved from ” speciflcation This may be used to abort a frame when some problem is detected after transmission has already started. The management interface controls the behavior of the PHY. The original MII transfers network data using 4-bit nibbles in each direction 4 transmit data bits, 4 receive data bits. Ethernet Computer buses Serial buses. The standard MII features a small set of registers: More recently, raising transmit error outside frame transmission is used to indicate the transmit data lines are being used specificafion special-purpose signalling.
At power up, using autonegotiationthe PHY usually adapts to whatever it is connected to unless settings are altered via the MDIO interface.
Speification should be able to drive 25 pF of capacitance which allows for PCB traces up to 0. This means a slight modification of the definition of CRS: Reference clock may be an input on both devices from an external clock source, gmoi may be driven from the MAC to the PHY.
The receiver clock is much simpler, with only one clock, which is recovered from the incoming data. The original MII design has been extended to support reduced signals and increased speeds.
However, at 1 ns edge rates a trace longer than about 2. This interface requires 9 signals, versus MII’s The media-independent specfication MII was originally defined as a standard interface to connect a Fast Ethernet i.
For receive, two data values are defined: