以HID類別實現USB to RS485轉換模組

Abstract

周邊裝置在與個人電腦連接時，使用通用序列匯流排(USB)是一個有彈性且簡單快速的連接方式。在工業界，許多的設備在做系統整合開發時，往往都是使用串列埠將各個系統與個人電腦做連接，但現今的個人電腦大多都不再提供串列埠的狀況下，大多都會使用市售的USB-to-RS232或RS485來連接個人電腦，但都需要額外開發與安裝驅動程式，並且隨著作業系統的更新必須再更新驅動程式。

本論文提出一種以HID(Human Interface Device)類別實現USB-to-RS485之方法，此方法利用USBHID裝置隨插即用的優勢，在完成設備與電腦連接之後不需要額外花費時間在電腦上安裝驅動程式，能夠減少安裝程序、降低人為疏失與開發人力資源、減低未來開發設備在量產之後需要售後服務的次數。

Universal Serial Bus (USB) is the standard communication port for most of the peripherals in the modern PCs. Nowadays, the common industrial devices still use the serial port to connect the PCs. In addition to the above method, there is a way to emulate a serial port by USB converter which can provide a Virtual COM Port. However, these solutions are not convenient, because the serial port is not provided in the modern PCs. Besides, by using the Virtual COM Port, the software drivers must be installed.

This thesis describes the implementation of USB to RS485 converter based on USB HID(Human Interface Device) protocol. In our research, once the devices connect to the PCs correctly, which can provide the direct communication of both sides. Precisely, this solution can improve the development time, installation steps and reduce the number of after-sales service of the products.