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Installing and using While Arduino software and hardware have made microcontroller projects accessible, many advanced users prefer to use MPLAB X, especially for PIC devices. Like the Arduino IDE, it is a free download. This article will step you through the process of creating your first MPLAB X project. T hose who have been dabbling with microproces- AVR parts (as described starting on page 88 of this issue). sors and microcontrollers for a long time may reMPLAB has evolved into MPLAB X, which is now Javamember a time when writing a program required based, and therefore runs on all major operating systems; intimate knowledge of instruction sets and memory maps. Windows, Mac and Linux. You had to hand-write assembly language or even machine For a long time, we’ve used this software and PICkit procode which would then have to be loaded into an EPROM. grammers to program microcontrollers for our projects, and Our early microprocessor projects, such as the 1989 Print- we see no reason to change that, especially with MPLAB er Buffer (siliconchip.com.au/Article/7380) or LED Message X now supporting AVR parts. Board (siliconchip.com.au/Series/255), There may be some out there also from 1989, used a Z80 microprofor whom microcontroller processor with separate RAM chips and gramming remains a mystery; an EPROM chip. perhaps you’re happy just buyAbout the same time came the first ing pre-programmed parts from PIC microcontrollers, with integrated the SILICON CHIP ONLINE SHOP, or program EPROM and in the next decyou just don’t have the need. But ade, flash memory. These were typicalyou may be interested in the proly programmed in assembly language, cess nonetheless. Or you might with the machine code created by an like to jump into the world of assembler program. microcontrollers. Flash-based devices such as the Rest assured that the process PIC16F84 meant it was finally possionly continues to get easier. In ble to quickly and easily update code this article, we’ll introduce and without having to manually erase an review the latest version of MiEEPROM under a UV lamp (or sunlight, crochip’s MPLAB X IDE. if you didn’t have a UV lamp). Once you’ve read through it, It was over ten years ago, in July you might also like to read the 2010, that we last gave an in-depth separate article on the new AVR ‘howto’ on programming PIC microDA family of microcontrollers controllers (siliconchip.com.au/Article/208). That article which are supported by MPLAB X. introduced the PICkit 3 programmer/debugger from MicroMPLAB X is not tied to that particular chip or developchip and their MPLAB software. ment board, but can be used with many Microchip microconMPLAB is a complete IDE (integrated development en- trollers, including virtually all PICs and many AVR MCUs. vironment). It’s integrated because it includes the ability to write programs in a high-level language (typically C) Microchip Technology and then compile, upload and even debug these programs. Microchip Technology is the company that makes PIC The PICkit 3 is still a handy device; we haven’t come microcontrollers. In 2016, they bought out Atmel, the makacross many PIC devices that it can’t program. But you will ers of 8-bit AVR microcontrollers (which are at the heart of probably have to switch to a PICkit 4 or Snap early Arduino boards such as the Uno). Atmel programmer if you want to work with the latest By Tim Blythman also made a range of 32-bit ARM-based micro48 Silicon Chip Australia’s electronics magazine siliconchip.com.au controllers (which are in some of the more recent Arduino boards). In a sense, these compete with Microchip’s MIPSbased PIC32 series. For a few years now, we have seen some crossover in features between the 8-bit PIC and AVR families. We described a then-new AVR part in January 2019, the ATtiny816 (siliconchip.com.au/Article/11372), and we’re following up with an article on the latest AVR DA parts this month (see page 88). Microchip Technology also produces the MPLAB X IDE software. It is available for free download, although some compiler optimisations (to produce smaller and faster code) are optional extras that you have to pay for. That said, you can get a lot done with the free version of the software. MPLAB X IDE MPLAB X IDE is an evolution of the earlier MPLAB IDE which dates back to 2001. The PICkit 2 programmer was introduced in 2005, and many people would have first come across MPLAB bundled onto a CD-ROM with their PICkit 2 purchase. MPLAB X was introduced in 2011 with support for the Mac and Linux platforms. Now, in 2020, the latest version of MPLAB X (version 5.40) is the first to drop support for 32-bit host processors (although it can, of course, program 32-bit microcontrollers). MPLAB X does not provide all features ‘out of the box’. Instead, compilers and other features are downloaded and added separately. In fact, it appears that in the future, new device support will be added using ‘Device Family Packs’ (DFPs – we speculated on the meaning of DFP in our ATtiny816 article!). What it does The User Guide for MPLAB X notes that it includes the following features: • a text editor (which also offers syntax highlighting and error checking) • a project manager • a software simulator Screen1: the default install directory includes the version number of MPLAB X, so it can be installed alongside earlier and later versions. This means you can try a new version before committing to it. siliconchip.com.au • a debugger engine offering breakpoints, single stepping and watch windows The following items can be added separately to the IDE: • compilers • programming frameworks (eg, Microchip’s Harmony series) • other tools As we noted earlier, programmers such as the PICkit devices are also needed to write firmware images to the microcontrollers. If you are experimenting with the AVR128DA48 Curiosity Nano board described in our article in this issue on the AVR DA family (or one of the other Curiosity Nano series), the programming function is built into the board, and no extra hardware is needed, apart from a USB cable. There is also the MPLAB Xpress Cloud-Based IDE, which runs in a browser. Installing MPLAB X Let’s get started with a basic introduction to the MPLAB X IDE. We’ll assume you’ve done some programming before, for example, using the Arduino IDE. The most basic steps involve writing code, compiling it and programming the resulting HEX file to the device. Under the Arduino IDE, the last two steps are combined in the function of the Upload button. The MPLAB X IDE can be downloaded from www. microchip.com/mplab/mplab-x-ide As we mentioned, the latest version at the time of writing (5.40) only supports 64-bit operating systems, so if you have a 32-bit processor, you may need to work with an older version instead. Legacy versions can be downloaded from www.microchip.com/development-tools/pic-and-dspicdownloads-archive There are minor differences with older versions, but you should be able to follow along; the big difference is that 5.40 is the first version to support the AVR128DA parts and thus is needed to work with the Curiosity Nano AVR128DA. Although MPLAB X supports other operating systems, much of the other software we use is still tied to Windows, so we will be using Windows 10 for our guide. But our Screen2: These options are new for version 5.40. There are separate options for the IDE (integrated development environment) and IPE (integrated programming environment). Choose the latter if you only wish to use MPLAB X for programming HEX files onto chips. The settings shown here are what we use, with support for 8-bit and 32-bit parts. Australia’s electronics magazine January 2021  49 Screen3: MPLAB X also installs drivers for devices such as programmers like the PICkit 4 and the programming interface on the Curiosity Nano AVR128DA. experience is that on Mac and Linux, it works in much the same way. The download for MPLAB X v5.40 is around 1GB and once installed, can take up to around 11GB. Installation is quite straightforward, and for the most part, the default options are fine (Screen1). It takes between about 10 minutes and an hour, depending on how fast your computer is. If you only wish to use MPLAB X for programming devices, then you might only want to install the IPE (integrated programming environment). There’s also the option to select whether you want support for 8-bit, 16-bit or 32bit devices; you will need 8-bit support for the AVR DA parts (see Screen2). The installer will also ask for permission to install some drivers (see Screen3). These are for devices such as programmers, so it’s a good idea to install them now too. When the MPLAB X installation is finished, you will also be prompted to install other items that you might typically need, such as a compiler – see Screen4. You will likely need to install at least one compiler, but if you want to install anything but the latest version, you’ll have to download them manually from siliconchip.com. au/link/ab4v The compilers are called XC8 (for 8-bit devices), XC16 and XC32 (for 32-bit devices like PIC32s). We currently use XC32 version v2.10 for our PIC32 projects, although some older projects use version v1.33. Also, the procedure for creating a “CFUNCTION” for a Micro- Screen5: the Free License for the XC8 Compiler works quite well. If you need the features of one of the Pro licenses (for example, more aggressive code optimisation), then it can be applied later. 50 Silicon Chip Screen4: to make proper use of MPLAB X, you need a compiler, so you should leave the top option checked. You can install compilers separately later, if required. mite only works with this older version. This is due to changes in the way some of the peripheral libraries work within the compiler. For 8-bit microcontrollers, we have previously used XC8 version v2.00. You might want to install one of these if you wish to modify some of our project code. The process here applies to version v2.20 of XC8, but other versions (and other compilers) should be fairly similar. If you want to build the code for the AVRDA family of chips, then you will need to install at least v2.20 of XC8. The first question you are asked when installing an XC compiler is about the licence type, as shown in Screen5. Initially, at least, the Free option is fine. A paid licence can be applied later if you need compiler optimisations (this means that, in general, your programs will be smaller and run faster). Then move onto the installation path; the default option is usually a good choice (Screen6), as the installer organises the different versions into folders, so it’s easy to check what versions are installed. The final step also relates to the licence. The Host ID (used for node-locked licences) is shown (see Screen7). Again, Screen6: the XC8 Compiler can be installed independently from MPLAB X, and different versions of it can be installed simultaneously. We sometimes use an older version of the XC32 compiler (for PIC32 parts) as it has a different set of libraries. Australia’s electronics magazine siliconchip.com.au Screen7: if you want to try the Pro license for XC8, there is a 60-day free trial. The easiest way to activate it is to rerun the installer and click the option shown here. for the free licence, you can simply click Next. At this stage, we have enough software installed to start compiling code, but let’s take a quick tour first. MPLAB X We’ll use the AVR128DA48 Curiosity Nano development board described in the accompanying article as an example. If you have one of these, plug it in now so that the software can recognise it. Open MPLAB X and choose New Project… from the File menu. The next step is to select a project type; we usually select “Standalone Project” (see Screen8). The other options are generally used to import existing projects from other programs. If you have installed the Harmony or MCC frameworks, then options for these will also appear. Harmony and the MPLAB Code Configurator (MCC) are the programming frameworks noted earlier; it is not necessary to install these to work with the AVR128DA48 Curiosity Nano. However, they may come in handy if you are working with some complex peripherals, especially USB. The next step is to choose the target part. For example, for the AVR128DA48 Curiosity Nano, the part will be AVR128DA48, because this board has the 48-pin variant. It’s possible to change this setting later (mid-project). For example, you may wish to port the code to a device from the same family with more pins, or even to a different device. Screen9: after creating a new project and adding a “main.c” file, you are presented with panels full of information. Project settings and properties can be found by right-clicking the project name at the top left and selecting “Properties”. siliconchip.com.au Screen8: as well as creating a Standalone project, you can also import Atmel Studio projects. If you have other frameworks (such as Harmony or MCC) installed, they appear as options here. On this tab, it’s also possible to select the programming tool. You should see the Curiosity Nano in the drop-down list. If you don’t have one of these, you can select “Simulator” or “No Tool”. The window will jump forward a few steps to allow a compiler to be chosen. Your only choice for the AVR128DA will be XC8 V2.20 or later (or its assembler, “pic-as”). Finally, you can choose a project name and location. We went with “AVR128DA48_blank”. The project is now created, but will (at a minimum) need to have at least one source code file. Right-click on the “Source Files” and click New -> avr-main.c. A file will appear in the main window and also at left. Your screen should now look like Screen9. Navigating the IDE The small window at top left allows you to navigate between projects and also individual files within a project. Below this, at the left, is the Dashboard. It shows important project information. Particularly handy are the Data and Program memory space bar graphs, which allow you to keep track of these resources as your code expands. At top right is the editor. If you have multiple files open, they will be shown by tabs along the top. The editor has the expected features like find and replace, but also syntax Screen10: the Project Properties window contains settings that are only changed rarely after the project is created. You might use the option at top right to modify a project to use a different part, for example, if you need more I/O pins and want to change to a larger member of the same family. Australia’s electronics magazine January 2021  51 highlighting and autocompletion. At lower right is the output window. Various stages of the development process are handled by different utilities (under the control of MPLAB X). For example, during compilation and upload, progress and warnings/errors (if any) are shown here. Of course, the windows can be moved around as needed, but we find that the defaults work quite well. The button with the green arrow coming out of the chip is for reading a device’s memory; typically this would be used to export the contents of flash memory to a HEX file, although this is usually not needed if you have compiled your own code. It might be handy, though, if your code writes data to flash (eg, its configuration) and you want to see what changes it has made. The button with the blue circular arrow is used to toggle the programmer’s device reset line, for example, if you wish to reset or disable the attached microcontroller during testing and debugging. The final button is used for hardware debugging. If you click this, your code is compiled with options allowing it to communicate with the programming tool, and is uploaded to the device. The MPLAB X IDE then switches to debugging mode, and some more buttons appear to control this. We explain the debugging process in more detail in the article on the AVR128DA, which starts on page 82. Handy hints MPLAB Xpress IDE Screen11: these buttons along the top of the MPLAB X window are for compiling and deploying your project to microcontroller hardware. The rightmost button initiates a debugging session. We can’t possibly detail all the features of MPLAB X, but we’ll briefly summarise those we use the most. It might pay to come back to this section while you’re working with the Curiosity Nano board. The main project properties can be opened by rightclicking on the project name in the Projects window (see Screen10). Many options from the initial project setup can be changed here. In fact, multiple configurations can be created, perhaps to target a variety of different processors or to help to port the project between compiler versions. The programmer can be changed too; it’s the first item under “Conf: [default]”. The “PKOB nano” is the programmer built into the Curiosity Nano (PKOB is short for PICkit On Board). You may have more need to tweak these settings when working with a standalone programmer. MPLAB X also includes an easy way to make a copy of a project. This can be handy if you don’t have some other form of version control in use, or you wish to use one project as the basis for another different project. Simply right-click on the project name in the Projects window and select “Copy...” Then supply a new name and click “Copy”. Just below the main menu items are commonly used tools, as shown in Screen11. The hammer icon builds (compiles) the project. Helpfully, the project name is shown, so you know which project you are building. This is handy if you have multiple projects open. The hammer and brush icon ‘cleans’ and builds. Usually, the build process only updates files that have changed since the last build. In contrast, a ‘clean and build’ ensures other changes like configuration settings changes are properly propagated through the compile process. For small projects, either process takes only a few seconds, so we find that we simply do a ‘clean and build’ most of the time. The next two buttons, labelled “Run” and “Make and Program Device”, perform the same function in most cases. The Run button can also be used to start the simulator for those devices that support it. Currently, this is only some PIC devices, so the AVR128DA is not supported by the simulator. 52 Silicon Chip It’s also worth noting that there is a cloud-based version of MPLAB X, called MPLAB Xpress IDE. It is not a replacement for the full IDE, but is a quick and easy way to have a look around at the platform’s features – see Screen 12. You can access it at the following link: https://www. microchip.com/mplab/mplab-xpress You can create a project, build it and even download a hex file. There’s also an option to export an MPLAB X project to work with the full IDE. Conclusion We’ve used MPLAB X for many years now, and it has improved over time. It’s especially handy that MPLAB X can now work with AVR parts as well as PICs, especially with in-circuit debugging (ICD). The latest version of the IDE doesn’t bring much in the way of new features for those that are familiar with using it to work with PIC microcontrollers. Indeed, many of the older versions are entirely adequate for coding, debugging and programming older PICs. But it is evolving to work with more microcontrollers, and SC these new AVR parts spread its reach even further. Screen12: the MPLAB Xpress IDE is an online IDE which allows you to export projects and compile HEX files. So it’s a good way to test out some of the features of MPLAB X without having to install it first. Australia’s electronics magazine siliconchip.com.au