AC207-DS02-R datasheet(11/60 Pages) BOARDCOM

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Preliminary Data Sheet

AC207

07/08/02

B roa dcom

Document

AC207-DS04-405-R

Functional Description

Page 1

Sect ion 1 : F un cti o n a l Descrip t io n

FUNCTIONAL DESCRIPTION

The AC207 is an unmanaged integrated 10/100 Mbps repeater with integrated bridge functions. The device provides eight

10/100BASE-TX twisted pair interface ports. The AC207 includes a built-in 2-segment bridge for 10/100-Mbps connection.

The AC207 provides the highest integration chip solution for dual speed hub system. The result is ultra low power

consumption that consumes less than 1A maximum when all ports are running 100BASE-TX full-speed. The built-in power

management function powers down the individual transceiver ports when not used (no cable detected) which further drives

down the power consumption and improves long-term reliability.

CLOCKS, RESET AND POWER MANAGEMENT FUNCTIONS

The AC207 requires a single 25-MHz clock signal at the CLK input pin. An internal PLL generates all of the clock frequencies

needed by the device from the single clock input.

The AC207 can be reset in two ways:

During initial power-on.

Hardware reset: A logic low signal of 10

µs pulse width applies to RST pin.

During reset, all mode pins latch in, the internal address table is initialized, and the internal state machine is reset to known

states. At the completion of the reset sequence, all ports are enabled for frame reception and transmission.

The AC207 offers the following power management:

•

Power-down mode: Refer to the Power-down register. For example, port 1 has a base address of Hex 00. During power-

down, the device is able to respond through the MDC/MDIO interface.

•

Energy detects mode: The device powers down all of the unused circuitry when the cable is not installed. The Energy

Detect (ED) circuit stays on to monitor incoming signals from the media. The MDC/MDIO interface is turned on in

response to any access transaction. The transmit circuit sends out a link pulse with minimum power consumption. If a

valid signal is received from the media, the device is powered up and resumes normal transmit/receive operation.

TRANSCEIVER AND TRANSMIT FUNCTION

In 100BASE-TX mode, the Transceiver transmits MLT-3 signal to the cable via isolation transformer. MLT-3 data is a three

level signal data. This data is scrambled when transmitted to the media. The MLT-3 data is synchronous to the 25-MHz clock.

In 10BASE-T mode, Manchester code is generated by the 10BASE-T core logic, which synthesizes through the output

waveshaping driver. This helps reduce any EMI emission, which eliminates the need for an external filter.

MII

The MII interface is for direct connection of an external device to the repeater. The transmit data on the MII interface is 4-bit

nibbles at 25/2.5-MHz rate. This MII interface is connected to the repeater via the MII TXD lines. The external device asserts

TX_EN during transmission, or forces an error in the encoded data using TX_ER.

AC207-DS02-R 数据表(PDF) 11 Page - Broadcom Corporation.

AC207-DS02-R 数据表(HTML) 11 Page - Broadcom Corporation.

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