Developing Projects for ESP32 Devices with Visual Studio

This tutorial shows how to develop projects for the Espressif ESP32 chip using Visual Studio, VisualGDB and the new ESP-IDF framework.

We will show how to build, program and debug a basic ESP32 program over JTAG on the Sparkfun ESP32 Thing board. In order to use JTAG with ESP32 you will need to connect the following pins to your JTAG programmer:

Pin name on ESP32 chip Signal on ESP32 Thing board Pin on the ESP32 board JTAG signal Pin on JTAG20 cable
+3.3V +3.3V 5 on J1 +3.3V 1
Reset CHIP_PU 6 on J1 SRST 3
GND GND 1 on J1 GND 4
MTDI 12 8 on J1 TDI 5
MTMS 14 9 on J1 TMS 7
MTCK 13 7 on J1 TCK 9
MTDO 15 11 on J2 TDO 13

If you are using a different ESP32 board, consult your board schematics to find the pin numbers corresponding to the signals listed above.

The assembled JTAG debugging setup for the ESP32 Thing board looks as follows:jtag

Before you begin, install VisualGDB 5.2 or later.

  1. Start Visual Studio and open the VisualGDB Embedded Project Wizard:01-prjname
  2. On the first page proceed with the default MSBuild subsystem and click “next”:02-binary
  3. On the next page select the ESP32 toolchain. If it is not installed, VisualGDB will download and install it automatically. If it is not shown in the wizard, install it via Tools->VisualGDB Package Manager. Then select the regular ESP32 device:03-esp32
  4. On the Sample Selection page pick the LEDBlink sample and enter the pin number where your LED is connected. On the Sparkfun ESP32 Thing board used in this tutorial the LED is connected to pin #5:04-blink
  5. On the debug settings page select your JTAG programmer. For Olimex ARM-USB-OCD-H and other FT2232-based ones, enable the “explicit speed” checkbox:debug
  6. You can test the OpenOCD settings and check for common driver problems by pressing the “Test settings” button:test
  7. Press “Finish” to generate your project. Due to a bug in the ESP-IDF framework, the projects built with no optimization (which is the default option for the debug configuration) will not work properly. To fix this, open Visual Studio Project Properties and change the optimization for the project to “Optimize for GDB (-Og)”. If you are using an older version of VisualGDB that does not show this option, simply enter -Og in the “Optimization” field:06-optimize
  8. Build your project via Ctrl-Shift-B:07-build
  9. Press F5 to start debugging. VisualGDB will automatically program the FLASH memory on the device:10-program
  10. After programming the program may produce a stop event in a random location inside the ESP32 libraries. You can safely ignore it by pressing “Continue”:break
  11. Once the programming is complete, the onboard LED should start blinking:conn
  12. Set a breakpoint somewhere in the blink_task() function and wait for it to trigger:12-breakpoint
  13. Note how the 2 ESP32 cores got mapped to 2 threads in the VisualGDB threads window:13-optimized
  14. Because we have enabled minimum optimizations, the unused variables will not be shown and stepping through code will sometimes look strange. You can fix this by disabling optimization for specific files that you want to debug. This will not break the ESP-IDF framework and will provide better debugging experience:14-unoptimize
  15. Another limitation of the ESP32 debugger is the inability to read local variables for the top-level functions. If you encounter this problem, while debugging your thread functions, simply wrap it with another function:

    15-param
  16. The ESP32 framework outputs a lot of debugging information to the COM port. On the Sparkfun ESP32 Thing board the COM port is connected to an on-board USB-to-COM converter. Use the Device Manager to find out its port number:16-usbser
  17. Then open VisualGDB Project Properties and enable the Raw Terminal on that COM port:17-terminal
  18. Next time you start debugging, VisualGDB will connect to the selected COM port and show various debug information printed by the ESP32 chip:18-terminal
  19. The ESP32 toolchain comes with peripheral register definitions derived from the ESP32 header files. You can view them via the Debug->Windows->Hardware Registers command in Visual Studio:19-hwreg

Note that the ESP32 tools have several known limitations that may interfere with debugging. Please refer to this post for a list of known issues and workarounds.