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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The original MII transfers specificationn data using 4-bit nibbles in each direction 4 transmit data bits, 4 receive data bits. This arrangement allows the MAC to operate without having to be aware of the link speed. Carrier sense is high when transmitting, receiving, or the medium is otherwise sensed as being in use.
When no clock can be recovered i. Four things vmii changed compared to the MII standard to achieve this:. The receive clock is recovered from the incoming signal during frame reception. This page was last edited on 19 Novemberat There are 32 addresses, each containing 16 bits. 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.
Drivers should be able to drive 25 pF of capacitance which allows for PCB traces up to 0. If a collision is detected, COL also goes high while the collision specifidation.
TTL signal levels are used for 5 V or 3. More recently, raising transmit error outside frame transmission is used to indicate the transmit data lines are being used for special-purpose signalling. However, at 1 ns edge rates a trace longer than about 2.
This requires the PCB to be designed to add a 1. Received clock signal recovered from incoming received data. At least the standard says specitication signals need not be treated as transmission lines.
The standard MII features a small set of registers: The receiver clock is much simpler, with only one clock, which is recovered from the incoming data.
Ethernet family of local area network technologies. For receive, two data values are defined: The management interface controls the behavior of the PHY.
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. The media-independent interface MII was originally defined as a standard interface to connect a Fast Ethernet i. At power up, using autonegotiationthe PHY usually adapts to whatever it spevification connected to unless settings are altered via the MDIO interface.
Views Read Edit View history. This may be used to abort a frame when some problem is detected after transmission has already started. Being media independent means that different types of PHY devices for connecting to different media i. 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 specificcation.
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.
Media-independent interface – Wikipedia
This interface requires 9 signals, versus MII’s The specification states that inputs should be 5 V tolerant, however, some popular chips with RMII interfaces are not 5 V tolerant. 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.
Reference clock may be an input on both devices from an external clock source, or may be driven from the MAC to the PHY. Transmit and receive path each use one differential pair for data and another differential pair for clock.