應用嵌入式DSP於觸控面板人機介面之研製

Human-Machine Interface via Touch Panel Based on DSP Microcontroller

本文發展以DSP微控制器為基礎的嵌入式系統應用於球拍穿線機的觸控式面板人機介面，DSP為Microchip公司型號dsPIC33EP512MU814的微控制器，設計全數位化的軟、硬體架構，整合TFTLCD觸控式面板、拉線驅動馬達、拉力感測器、EEPROM外部記憶體等裝置，達到球拍穿線機友善的人機穿線介面和拉力精密控制的目的。首先，根據球拍穿線機的功能需求設計TFTLCD面板所需的人機畫面，每個畫面包括背景（Background）、圖標（Icon）和按鍵位置，再以Adobe Illustractor繪圖軟體裁剪圖片，經由轉圖軟體轉成BIN檔後燒入觸控面板的記憶體。以MPLAB IDE開發平台和C30編譯器撰寫DSP的嵌入式程式，設計各種運算碼（Operation code, OP-code）利用UART通訊與TFTLCD觸控面板溝通。以I2C通訊讀取/儲存系統參數於EEPROM記憶體。並且透過軟體開通DSP內建的A/D和PWM功能模組，以擷取拉力感測器的類比訊號，發展拉力控制法則據以控制拉線馬達得到所要的拉線磅數。本文所發展的DSP嵌入式系統，不但在觸控式人機介面的操作能更加直覺友善，並且以DSP的內建功能模組取代周邊的硬體電路，簡化電子元件的數目，達到全數位化目的。最後，以所發展的觸控面板嵌入式人機介面應用於實際的穿線機，透過各種實驗驗證本文所提方法的優越性。

An embedded system based on a digital signal processor（DSP）microcontroller was developed for the touch-panel-based human–machine interface of a racket stringing machine. The DSP microcontroller was the dsPIC33EP512MU814 from Microchip. This system has a fully digital software and hardware architecture and comprises a thin-film transistor（TFT）liquid crystal display（LCD）touch panel, a string-pulling motor, a tension sensor, and EEPROM external memory. The goal was to provide precise tension control for the racket stringing machine in a user-friendly manner. The human–machine interface screens for the TFT LCD panel were first designed considering the functional requirements of the racket stringing machine. Each screen includes a background, icons, and buttons. Images were cropped using Adobe Illustrator and converted into binary files that were subsequently burned into the touch panel's memory. Embedded programs for the DSP are written using the MPLAB development environment with the C30 compiler. Various operation codes were designed to communicate with the TFT LCD touch panel over the universal asynchronous receiver-transmitter protocol. The system parameters were read from and stored in EEPROM memory over the I2C protocol. To capture analog signals from the tension sensor, the built-in analog-to-digital and pulse-width modulation functional modules of the DSP were enabled through software. A tension control algorithm was developed to control the string-pulling motor to achieve the desired string tension. The touch-based human–machine interface of the DSP embedded system is not only intuitive and user-friendly but also simpler than other systems due to the use of the DSP's built-in functional modules. These modules replace peripheral hardware circuits, thus reducing the required number of electronic components and allowing for a fully digital design. The developed system was applied to an actual stringing machine and its effectiveness was experimentally validated.