debug

Modding a Chinese ST‑LINK V2 clone to add SWO support

09.06.2026 0, ? Software and Hardware Usage

Recently a colleague mentioned that Luatos Mall was running a promotion for the AIR32F103 BluePill development boardhttps://wiki.luatos.com/_static/bom/BluePill.html). At 9.9 RMB you get a board plus an extra AIR32F103CCT6 chip. I had never used STM32 MCUs before, so I picked one up to study, at least as a collectible.

After receiving it, I quickly learned from Luatos documentation and searched for STM32 beginner guides online. I discovered various ways to upload programs. Since I had previously bought an ST‑LINK V2 (originally intended for flashing firmware to a WY815P soldering station), I chose to test using ST‑LINK SWD. After soldering headers and wiring according to the silkscreen, the PC recognized the debugger with STM32 ST‑LINK Utility. I then installed the research version of Keil (v5.23 from the netdisk bundled with the ST‑LINK), added the AIR32 software library per Luatos wiki, learned GPIO basics, and successfully lit the onboard LED. At this point I realized how much simpler Arduino is 😂. Breakpoint debugging in Keil also worked. But then I hit a problem: unlike Arduino Nano, which can easily use the IDE serial monitor for logs and command‑line interaction, this setup had no simple way to view printf output. So I spent time researching.

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The source file is different from when the module was built.

04.06.2026 0, ? Design & Development

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Source file: D:\Projects\StereoMatch\stereomatcher.cpp

Module: D:\Projects\StereoMatch\Debug\StereoMatch.exe

Process: [4024] StereoMatch.exe

The source file is different from when the module was built. Would you like the debugger to use it anyway?

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At StereoMatcher.cpp, line 166 (‘ComputeCorrespondence()’, line 128)

The breakpoint will not currently be hit. The source code is different from the original version.

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FFmpeg native script building Windows debug version debugging and tracing issues

24.05.2026 0, ? Design & Development

This time I want to record what feels like a rather hardcore problem. Due to the title length limit, it’s impossible to accurately express all the issues. For example, when debugging FFmpeg code with breakpoints and single‑stepping, the code does not execute in order, jumps around unpredictably, and when checking local variables near a breakpoint, their values cannot be displayed correctly, such as this:

The local variable “offset” cannot show its current value and instead displays “Variable is optimized away and not available.” From the literal meaning, we can guess that the compiler optimized the code, such as inlining and removing intermediate variables, so they can no longer be seen.

However, FFmpeg’s configure parameters for building the debug version do include:

–disable-optimizations –enable-debug –disable-stripping

These officially documented debug build parameters. So why do we still encounter all the debugging obstacles described above, which look like the result of compiler optimizations?

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