Since microcontrollers themselves lack programming capabilities, turning them into application products requires both hardware and software development tools. Software development begins with creating the PIC microcontroller's source code (mnemonic program) using relevant editing software in a specific format. This source code is then assembled. After assembly, users can use simulation debugging software (low-cost) or a hardware in-circuit emulator (high-cost) to run and debug the target program (machine code) to identify and correct errors. After debugging, modification, and reassembly, the modified target program can be programmed into the user's PIC chip using a hardware programmer. Finally, the programmed (i.e., hardened) chip is inserted into the user board (experimental board) for offline operation. If problems persist (usually with multiple programs), the hardware circuitry and software design are checked, errors are identified and corrected, and the process is repeated with reassembly and debugging until offline operation is successful. Along with its PIC series microcontroller products, Microchip also launched corresponding software and hardware development tools, such as the PIC in-circuit emulator, MPLAB integrated development software, MPSIM software emulator, MPASM macro assembler, and PIC general-purpose programmer. Furthermore, domestic development of PIC series microcontrollers has been rapid, with many companies and research institutes launching corresponding development devices. These range from low-cost software emulators and programmers suitable for beginners to mid-to-high-end development devices for product development. Some high-end development devices even support C compilers (such as MP-C) and fuzzy logic development systems. These development devices can run independently or connected to a PC. In short, the tools for developing PIC series microcontrollers are not only mature but also diverse. Source code assembly for PIC series microcontrollers on a PC can be performed under both DOS and Windows environments. The following will introduce the methods and steps for source code assembly under Windows. MPLAB Integrated Development Software for Windows PIC MPLAB is an integrated development software provided by Microchip for Windows PCs used in the development of PIC series microcontroller products. MPLAB has evolved to various versions from its early days to the present, such as MPLAB V3.01, V3.02, V4.0, V4.99, and V5.0. All versions are backward compatible, so despite the large variety of PIC microcontrollers, users only need to select the corresponding version of MPLAB integrated development software to achieve their development goals. (1) MPLAB Features and Installation MPLAB is an easy-to-learn and easy-to-use integrated development tool for PIC microcontroller products. This software consists of the MPLAB editor, MPLAB project manager, MPASM assembler (Windows version), and MPLAB-SIM simulation debugging program. MPLAB can help you debug source code, observe program flow, debug and optimize firmware production design for PIC microcontroller applications. The functions and usage of the aforementioned software will be introduced through examples in the next few issues of this newspaper. The hardware and software configuration requirements for the MPLAB integrated development software are as follows: Microsoft Windows 3.X, 95 and 98 versions are all acceptable; standard keyboard and mouse; 4MB (preferably 16MB or more) of memory and a VGA or higher monitor, etc. MPLAB is easy to install. Any user familiar with PCs can install it using the MPLAB SETUP.EXE file and related prompts on the disk or CD-ROM. If you are a beginner, you can ask a computer expert to install it. When installing MPLAB software, it is best to paste the Microchip/MPLAB shortcut icon on the screen for easy operation. (2) MPLAB Desktop System The biggest difference between the Windows operating system and the DOS operating system is the extensive use of graphical operation interface. Therefore, dialog boxes are the things that users encounter most often when operating Windows. All functions of MPLAB can be operated through the menu commands in the MPLAB desktop (dialog box). After you have installed the MPLAB integrated development software on your PC, turn on the PC and click the Microchip shortcut icon on the screen with the mouse to see the MPLAB desktop on the screen, as shown in the attached figure (V4.99 version). The desktop is a resizable window. The top left of the MPLAB desktop displays the title bar (MPLAB); below the title bar is the menu bar (MENU), below that is the toolbar, and at the bottom is the status bar. The menu bar in the desktop window is a drop-down menu. MPLAB has multiple menu options (9 in V3.22 and V4.99, and 8 in V3.01). All MPLAB functions can be accessed through the drop-down menu. Underlined characters in the menu represent key accelerators; clicking these keys while the menu is in the drop-down menu immediately executes the corresponding function. The functions of the various MPLAB menus will be explained in detail through specific program assembly application examples. Editor: He Shiping