The STLINK-V3 is one of the best ways to debug and program an STM32 microcontroller. It transfers data faster than the previous generation and with a lot more flexibility, thanks in part to its STDC-14 connector and its support of a virtual COM port. Besides the STLINK-V3SET, ST offers the STLINK-V3MINIE and STLINK-V3MODS, which don’t support adapter boards but offer a smaller design for engineers looking for portability. However, all probes observe one principle: they must work regardless of unexpected edge cases or new applications. This latest STLINK thus focuses on versatility thanks to a clever interface, a robust connector, and the presence of various modules to tailor our offerings to more developers.
When Professor Zhu of the University of Maine presented a curriculum teaching embedded systems to undergraduates with ST’s drone kit, educators asked about the debugging tools. The drone kit is too small to integrate the STLINK interface, thus requiring an external module. The audience’s response to the new STLINK features and probe selection was overwhelmingly positive. To better understand why ST continues to release new modules, including the STLINK-V3MINIE, our first standalone probe with a USB-C port, let’s explore five reasons behind the success of our latest in-circuit debugger/programmer.
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1. STLINK-V3: A Strong Heritage
While the new STLINK is increasingly popular, ST-LINK/V2, the previous generation, continues to have a following. The first ST-LINK/V2 standalone device came out in 2011. It meant that developers could rapidly connect the in-circuit debugger/programmer between their board and their PC to compile their code, send their application to their MCU, benefit from unlimited breakpoints in RAM, and figure out if the system could run or if an error caused problems. The solution is highly popular amongst professionals and large engineering teams. Consequently, we continue to sell and support our ST-LINK/V2 devices as companies transition to the new interface.
Our investments in ST-LINK/V2 also serve as a witness to our commitment to longevity. Teams pondering whether to adopt or switch to the latest STLINK can simply check our track record. We’ve launched at least one new probe every year to meet new demands. Whether to help developers work with low-power microcontrollers, enjoy a smaller form factor when they are on the go, or adopt new ports, like USB-C, ST continues to improve version 3, knowing that, just like ST-LINK/V2, the interface will continue to live on for a very long time.
2. A Faster In-Circuit Debugger/Programmer
Data transfers are the bread and butter of this platform, which explains why the first significant architectural difference between ST-LINK/V2 and STLINK-V3 is the latter’s compatibility with the USB 2.0 Hi-Speed interface. Previously, developers had to contend with a 12 Mbit/s USB 2.0 Full-Speed data rate, which could be cumbersome when uploading large applications. Comparatively, the latter offers theoretical speeds of up to 480 Mbit/s.
Furthermore, beyond the simple interface upgrade, ST also implemented multiple optimizations of its algorithms and processes, making this a thorough architectural overhaul instead of a simple speed bump. Hence, the increase in productivity for teams that upload large applications multiple times a day is highly noticeable.
Beyond better speed, all STLINK-V3 boards, except for the daughter cards, offer mass storage support for a more convenient upload process. Previously, only the ST-LINK/V2 available on some of our development boards, like our Nucleo boards, offered this feature. However, with the new probes, engineers can connect the in-circuit debugger/programmer and then drag and drop binaries to upload them in no time. This is particularly useful for developers wanting to quickly experiment with a demo application on a custom PCB and who would rather not have to compile their code and send it through their IDE. It also makes swapping demos far more convenient, especially in the field.
3. A More Flexible Tool
The ST 14-pin debug, the STDC-14, present on the STLINK-V3SET, the B-STLINK-VOLT, and the STLINK-V3MINIE is another reason for the modules’ flexibility. When users open their packaging, they will find the traditional MIPI 10-pin cable, which is relatively compact and very popular, and a new STDC 14-pin cable. The MIPI 10-pin version doesn’t support a virtual COM port. As a result, we developed an extension of the MIPI-10 connector that uses four additional pins to offer more features.
This is important because until now, engineers had to use extra cables and find workarounds to get a virtual COM port when they didn’t have the ST-LINK/V2 built into their development board. Thanks to the STDC-14, using a virtual COM port is more practical. Similarly, the in-circuit debugger/programmer opens the door to an entirely new set of features as it allows PC developers to drive a couple of GPIOs from the new ST-LINK thanks to the DLL API present in STM32CubeProgrammer. Hence, teams can potentially add LEDs that light up as a sign that a routine runs well, control other peripherals, or even use proprietary extensions via these IOs.
4. A Versatile Companion
The new architecture is more versatile than the previous generation thanks to its support of JTAG (Joint Test Action Group) and SWD, as well as the STDC-14 connector and its virtual COM port. Moreover, the STLINK-V3SET goes a step further with the ability to add extension cards on the debugger/programmer, such as the B-STLINK-ISOL and the B-STLINK-VOLT (more on them later), to increase its functionalities.
Another example of our platform’s flexibility is the availability of a complementary interface board that allows developers to upload firmware through the SPI, I2C, or UART interface. This extension card serves as a bridge between the target board and the PC. Using the STM32CubeProgrammer software tool, either in a command line or graphical interface mode, developers can use this bridge to facilitate maintenance operations without leaving a debug port open, which represents a severe security breach.
Another example is Percepio and its Tracealyzer for the STLINK-V3SET. Tracealyzer is a trace visualization tool for developers of RTOS-based software systems, providing over 30 graphical views and live visualization. Tracealyzer supports STLINK-V3SET, allowing for a comprehensive insight into STM32 software during development, debugging, validation, and optimization.
5. A Custom Approach to Developers’ Needs
The STLINK-V3SET will attract developers with more extensive needs. The module comes with more cables as it is compatible with the larger and still valuable MIPI-20 connector. It also has a height-adjustable casing to shield the stack of boards on top of the STLINK-V3SET so users can neatly house their extension cards. The STLINK-V3SET is also the only one to offer compatibility with SWIM (Single Wire Interface Module) to ensure teams can program and debug an STM8. As a result, it is the largest probe ST currently offers and will attract engineers working in a lab or those that prioritize features over portability.
The B-STLINK-VOLT is an adapter board allowing the STLINK-V3SET in-circuit debugger/programmer probe to work with STM32 microcontrollers (MCU) that draw less than the traditional 3.3 V. Put simply, it’s a conversion circuit that lowers the voltage down to as little as 1.65 V, thus ensuring developers can use STLINK-V3 with systems relying on a small battery, for instance. Users find the same STDC-14 connector to debug and program their MCU using JTAG, SWD, SWV, or VCP while still communicating using SPI, UART, I2C, CAN, or GPIOs. We also updated our user manual to cover the various jumper configurations and the board’s installation into the STLINK-V3SET case.
Until the launch of the B-STLINK-VOLT, teams using an STM32 MCU at 1.8 V had to rely on STLINK-V2. The new STLINK first focused on performance, and a voltage reduction necessarily lowered the frequency of the various interfaces. Hence, when STLINK-V3 was just new, most engineers used the previous generation of probes since they wouldn’t have seen a change in data transfers. However, now that the latest version is highly popular, we decided to launch the B-STLINK-VOLT and the B-STLINK-ISOL, thus opening STLINK to a whole new range of STM32 applications. Please note that working with STM8 doesn’t require such an adapter board since the MCU includes a voltage conversion circuit.
B-STLINK-ISOL is a module for the STLINK-V3SET that offers galvanic isolation and works with microcontrollers that draw less than 3.3 V. When connected to the STDC14 connector of the STLINK-V3SET, B-STLINK-ISOL serves as a traditional debugging probe. When connected between the STLINK-V3SET and its adapter board MB1440, B-STLINK-ISOL ensures developers can access all signals and connectors on low-power MCUs. Hence, it offers similar features as the B-STLINK-VOLT but with the added benefit of galvanic isolation, which protects the PC and the board. Indeed, ground loops may cause damage or interferences when two circuits use the same ground. Galvanic isolation solves this issue.
The STLINK-V3MODS is the smallest (15 x 30 mm) board today and the only one engineers can directly solder onto a PCB to vastly increase their prototype’s appeal. Additionally, the board receives power through its micro-USB connector, thus simplifying its integration into a custom design. The system only supports 3.3 V STM32 MCUs and provides compatibility for SWD, JTAG, and VCP. The solution also supports bridge interfaces, such as SPI, I2C, CAN, and GPIOs, to facilitate communication with the embedded system. Hence, developers looking to benefit from the speeds and versatility of STLINK-V3, while seeking something more compact than the STLINK-V3SET, will turn to the STLINK-V3MODS to facilitate their prototyping operations.
STLINK-V3MINIE is the newest model and the first to include a USB-C port. It is slightly longer than the STLINK-V3MODS at 15 mm x 42 mm; it also stands out thanks to its support for low-power microcontrollers. Indeed, it’s our first standalone probe compatible with the latest STLINK to support 1.65 V. Developers working on a 1.8 V application don’t need to grab the STLINK-V3SET and one of its expansion cards. Its small size primarily targets developers that must constantly flash firmware in the field. As a result, it supports SWD, SWV, and VCP thanks to its STDC14 connector. However, the STLINK-V3MINIE doesn’t supply power to the embedded system due to its size.