DM9000A Ethernet 控制器应用笔记V1.20：接口与设计指南

DM9000A Application Notes Version 1.20, dated April 22, 2005, is a comprehensive technical reference manual for the Davicom Semiconductor DM9000A Ethernet controller, which features a General Processor Interface (GPI). This document serves as a guide for engineers and developers working with the device, covering essential aspects such as hardware design, signal connections, power management, and programming procedures. 1. Introduction: - The document begins by providing an overview of the DM9000A, describing it as a 16/8-bit Ethernet controller designed to interface seamlessly with general-purpose processors. It sets the stage for understanding its capabilities and how it can be integrated into various system architectures. 2. General Processor Bus Description: - Key to the DM9000A's functionality is its communication with the processor. Section 2 details the typical signal connections required, including a pin function table and modes for the 8/16-bit parallel bus. It outlines how to configure the controller to work in different data transfer widths. 3. System Hardware Design: - This section guides users through selecting the right chip for their application, setting strap pins for configuration, and managing the Serial EEPROM for storage and initialization data. The GPIOPins are also discussed, along with reference schematics for both 8-bit and 16-bit processor configurations. 4. Reset Operation and PHY Power-Down Mode: - Power management is critical for efficient operation. The notes cover power-on reset, software reset, and the PHY (Physical Layer) power-down mode. Users learn about GPR (Global Programming Reset) and PHYPD settings, as well as the proper configuration of PHY registers during this power-down state. 5. Programming the DM9000A: - The heart of the document is the programming guide, which explains how to read and write register values on the controller. It walks users through driver initialization steps and provides detailed instructions on accessing and modifying EEPROM data, including reading and writing processes. In summary, the DM9000A Application Notes Version 1.20 serve as a valuable resource for anyone working with the Davicom DM9000A Ethernet controller. It covers not only the technical specifications but also the practical considerations needed for a successful integration with a general processor, including signal handling, power management, and programming techniques. This document ensures that developers can efficiently utilize the controller's features to build robust and reliable Ethernet-based systems.