Technical Datasheet: DMEP Datasheet Through the Media Independent Interface (MII), the DM connects to the Medium Access Control (MAC) layer, . Details, datasheet, quote on part number: DM Company, Davicom Semiconductor Incorporated. Datasheet, Download DM datasheet. Quote. DM Datasheet PDF Download – 10/ Mbps FAST ETHERNET PHYSICAL LAYER SINGLE CHIP TRANSCEIVER, DM data sheet.

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The DM provides a strong support for the autonegotiation function utilizing automatic media speed and protocol selection. Single low-power Supply of 3. In 10Mbps, the input is ignored. This clock is provided by management entity, and it is up to 2. Asserted datawheet whenever there is a status change link, speed, duplex. In repeater mode or full-duplex mode, this signal is asserted high to indicate the presence of carrier due to receive activity only.

Collision Daatsheet Asserted high to indicate the detection of the collision conditions in 10Mbps and Mbps half-duplex mode. In full-duplex mode, this signal is always logical 0. This pin is always pulled low except used as reduced MII. Test mode control pin. This pin is also used to select Repeater or Node mode. Active high enables receive signals RXD[0: Active low on this input tri-states these output pins.

In node application, this pin should be pulled high.

(PDF) DM9161 Datasheet download

In repeater application, this pin may be connected to a repeater controller. Reset Active low dqtasheet that initializes the DM Differential data is received from the media. O Differential transmit pair. Differential data is transmitted to the media in TP mode. LI Active states indicate Full-duplex mode. Active states see LED U configuration. Active states see LED configuration. It is U also an activity LED function when transmitting or receiving data.

All LED pins are dual function pins, which can be configured as either active high or low by pulling them low or high accordingly. If the pin is pulled high, the LED is active low datasneet reset. Likewise, if the pin is pulled low, the LED is active high. Figure 1 shows the major functional blocks implemented in the DM The MII consists of a nibble wide receive data bus, a nibble wide transmit data bus, and control signals to facilitate data transfers between the PHY and the Reconciliation layer.

If TXER is dm911 for one or more clock periods, and TXEN is asserted, the PHY will emit one or more symbols that are not part of the valid data delimiter set somewhere in the frame being transmitted. To interpret a receive frame correctly by the reconciliation sublayer, RXDV must encompass the frame starting no later than the Start-of-Frame delimiter and excluding any EndStream delimiter.

RXER will be asserted for 1 or more clock periods to indicate to the reconciliation sublayer that an error was detected somewhere in the frame being transmitted from the PHY to the reconciliation sublayer. CRS carrier sense is asserted by the PHY when either the transmit or receive medium is non-idle and deasserted by the PHY when the transmit and receive medium are idle.

The on-chip clock circuit converts the 25MHz clock into a MHz clock for internal use. The interface specification defines a dedicated receive data bus and a dedicated transmit data bus. These two busses include various controls and signal indications that facilitate data transfers between the DM and the Reconciliation layer. The transmitter section contains the following functional blocks: This conversion is required for control and packet data to be combined in code groups.

The 4B5B encoder continues to replace subsequent 4B preamble and data nibbles with corresponding 5B code-groups. Scrambler The scrambler is required to control the radiated emissions EMI by spreading dqtasheet transmit energy across the frequency spectrum at the media connector and on the twisted pair cable in Base-TX operation. By scrambling the data, the total energy presented to the cable is randomly distributed over a wide frequency range. Without the scrambler, energy dayasheet on the cable could peak beyond FCC limitations at frequencies related to repeated 5B sequences like continuous transmission of IDLE symbols.


The result is a scrambled data stream with sufficient randomization to decrease radiated emissions at critical frequencies. Parallel to Serial Dj9161 The Parallel to Serial Converter receives parallel 5B scrambled data from the scrambler and serializes it converts it from a parallel to a serial data stream. MLT-3 Driver The two binary data streams created at the MLT-3 converter are fed to the datawheet pair output driver which converts these streams to current sources and alternately drives either side of the transmit transformer primary winding resulting in a minimal current MLT-3 signal.

Refer to figure 4 for the block diagram of the MLT-3 converter. Binary plus Binary In. The receive section contains the following functional blocks: Adaptive Equalizer When transmitting data at high speeds over copper twisted pair cable, attenuation based on frequency becomes a concern.

In high speed twisted pair signaling, the frequency content of the transmitted signal can vary greatly during normal operation based on the randomness of the scrambled data stream. This variation in signal attenuation caused by frequency variations must be compensated for to ensure the integrity of the received data. In order to ensure quality transmission when employing MLT-3 encoding, the compensation must be able to adapt to various cable lengths and cable types depending on the installed environment.

DM Datasheet(PDF) – Davicom Semiconductor, Inc.

The selection of long cable lengths for a given implementation requires significant compensation which will be over-kill in a situation that includes shorter, less attenuating cable lengths. Conversely, the selection of short or intermediate cable lengths requiring less compensation will cause serious under-compensation for longer length cables. Therefore, the compensation or equalization must be adaptive to ensure proper conditioning of the received signal independent of the cable length.

The Clock Recovery Module locks onto the data stream and extracts the Mhz reference clock. This conversion process must be reversed on the receive end. Descrambler Because of the scrambling process required to control the radiated emissions of transmit data streams, the receiver must descramble the receive data streams.

The descrambler receives scrambled parallel data streams from the Serial to Parallel converter, descrambles the data streams, and presents the data streams to the Code Group alignment block.

Data processed for transmit is presented to the Dataaheet interface in nibble format, converted to a serial bit stream, then Manchester encoded. When receiving, the Manchester encoded bit stream is decoded and datashert into nibble format for presentation to the MII interface. Collision Detection For half-duplex operation, a collision is detected when the transmit and receive channels are active simultaneously. Collision detection is disabled in Full Duplex operation.

During full-duplex mode, CRS is asserted only during receive operations. Auto-Negotiation The objective of Auto-negotiation is to provide a means to exchange information between segment linked devices and to automatically configure both devices to take maximum advantage of their abilities.

It is important to note that Autonegotiation does not test the link segment characteristics. The Auto-Negotiation function provides a means for a device to advertise supported modes of operation to a remote dayasheet partner, acknowledge the receipt and understanding of common modes of operation, and to reject un-shared modes of operation.

This allows devices on both ends of a segment daatasheet establish a link at the best common mode of operation. If more than one common mode exists between the two devices, a mechanism is provided to allow the devices to resolve to a single mode of operation using a predetermined priority resolution function.


During Parallel detection there is no exchange of configuration information, instead, the receive signal is examined. If it is discovered that the datasheer matches a technology that the receiving device supports, a connection will be automatically established using that technology.

This allows devices that do not support Auto-negotiation but support a common mode of operation to establish a link. MII Serial Management The MII serial management interface consists of a data interface, basic register set, and a serial management interface to the datashert set. Through this interface it is possible to xm9161 and configure multiple PHY devices, get status and error information, and determine the type and capabilities of the attached PHY device s.

Following the turnaround time, bit data is read from or written onto management registers. Serial Management Dm91661 The serial control interface uses a simple two-wired serial interface to obtain and control the status of the physical layer through the MII interface.

The MDIO pin is bi-directional and may be shared by up to 32 devices. In case of cable disconnection, DM will automatically turn off the power and enter the Power Reduced mode, regardless of catasheet operation mode being N-way auto-negotiation or forced mode.

While in the Power Dtasheet mode, the transmit circuit will continue sending out fast ddm9161 pules with minimum power consumption. If a valid signal is detected from the media, which might be N-way fast link pules, 10Base-T normal link pules, or Base-TX MLT3 signals, the device wakes up and resumes normal operation mode.

Automatic reduced power down mode can be disabled by writing Zero to Reg. This bit, which is self-clearing, will keep returning a value of one until the reset process is completed Loopback: When auto-negotiation is enabled and bit 12 is set, this bit will return auto-negotiation selected medium type.

While in the power-down state, the PHY should respond to management transactions. During the transition to power-down state and while in the power-down state, the PHY should not generate spurious signals on the MII. Re-initiates the auto-negotiation process. When auto-negotiation is disabled bit 12 of this register clearedthis bit has no function datasehet it should be cleared. This bit is self-clearing and it will keep returning dmm9161 value of 1 until autonegotiation dm91161 initiated by the DM Duplex selection is allowed when Autonegotiation is disabled bit 12 of this register is cleared.

Read as 0, ignore on write 0. Read as 0, ignore on write MII frame preamble suppression: Fault criteria and detection method is DM implementation specific. Jabber conditions will set this bit unless it is cleared by a read to this register through a management interface or a DM reset. This bit works only in 10Mbps mode Extended capability: The Identifier consists of a concatenation of the Organizationally Unique Identifier OUIa vendor’s model number, and a model revision number.

This register stores bit 3 to 18 of the OUI E to bit 15 to 0 of this register respectively. Bit 19 to 24 of the OUI E are mapped to bit 15 to 10 of this register respectively Vendor model number: Six bits of daatsheet model number mapped to bit 9 to 4 most significant bit to bit 9 Model revision number: Four bits of vendor model dm9611 number mapped to bit 3 to 0 most significant bit to bit 3 24 Final Version: Software should not attempt to write to this bit.

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