NS公司的双路10/100Mbps以太网物理层收发器DP83849有两个完全独立的10/100Mbps端口，适合于多端口的应用。它支持MII和RMII接口，提供功能强大的电缆诊断工具，以保证网络的运行和维护。本文介绍了DP83849以太网收发器的主要性能，方框图以及系统应用方框图和评估板的详细电路图。

DP83849I PHYTER DUAL Industrial Temperature with Flexible Port Switching Dual Port 10/100 Mb/s Ethernet Physical Layer Transceiver General Description
The number of applications requiring Ethernet Con-nectivity continues to expand. Along with this increased market demand is a change in application requirements. Where single channel Ethernet used to be sufficient, many applications such as wireless remote base stations and industrial networking now require DUAL Port functionality for redundancy or sys-tem management. The DP83849I is a highly reliable, feature rich device perfectly suited for industrial applications enabling Ethernet on the factory floor. The DP83849I features two fully independent 10/100 ports for multi-port applications. NATIONAL’s unique port switching capability also allows the two ports to be configured to provide fully integrated range extension, media conversion, hardware based failover and port monitoring. The DP83849I provides optimum flexibility in MPU selection by supporting both MII and RMII interfaces. In addition this device includes a powerful new diag-nostics tool to ensure initial network operation and maintenance. In addition to the TDR scheme, commonly used for detecting faults during installation, NATIONAL’s innovative cable diagnostics provides for real time continuous monitoring of the link quality. This allows the system designer to implement a fault prediction mechanism to detect and warn of changing or deteriorating link conditions. With the DP83849I, National Semiconductor continues to build on its Ethernet expertise and leadership position by providing a powerful combination of features and flexibility, easing Ethernet implementation for the system designer

主要性能：

Low-power 3.3V, 0.18μm CMOS technology
Low power consumption <600mW Typical
3.3V MAC Interface
Auto-MDIX for 10/100 Mb/s
Energy Detection Mode
Flexible MII Port Assignment
Dynamic Integrity Utility
Dynamic Link Quality Monitoring
TDR based Cable Diagnostic and Cable Length Detection
Optimized Latency for Real Time Ethernet Operation
Reference Clock out
RMII Rev. 1.2 Interface (configurable)
SNI Interface (configurable)
MII Serial Management Interface (MDC and MDIO)
IEEE 802.3u MII
IEEE 802.3u Auto-Negotiation and Parallel Detection
IEEE 802.3u ENDEC, 10BASE-T transceivers and filters
IEEE 802.3u PCS, 100BASE-TX transceivers and filters
IEEE 1149.1 JTAG
Integrated ANSI X3.263 compliant TP-PMD physical sub-layer with adaptive equalization and Baseline Wander compensation
Programmable LED support for Link, 10 /100 Mb/s Mode, Activ-ity, Duplex and Collision Detect
Single register access for complete PHY status
10/100 Mb/s packet BIST (Built in Self Test)
80-pin TQFP package (12mm x 12mm)

应用：
Medical Instrumentation
Factory Automation
Motor & Motion Control
Wireless Remote Base Station
General Embedded Applications



图1。DP83849系统应用方框图。



图2。DP83849功能方框图。

DP83849I Functional Block Diagram



图3。DP83849评估板电路图（1）



图4。DP83849评估板电路图（2）



图5。DP83849评估板电路图（3）



图6。DP83849评估板电路图（4）



图7。DP83849评估板电路图（5）



图8。DP83849评估板电路图（6）



图9。DP83849评估板电路图（7）

详情请见：

>http://www.national.com/ds/DP/DP83849I.pdf

来源：中电网