Debugging Feather ESP32: missing peripherals information, watch variables, number of breakpoints

[erich]

Hi,
First of all thanks for the great IDE and all the effort you put into it!

My environment looks like this:
macOS Catalina 10.15.4
Visual Studio Code 1.45.1
PlatformIO Core 4.3.3 Home 3.2.2
Probe: Segger J-Link EDU / SW V6.72d
Hardware: Adafruit Feather ESP32

I successfully wired everything up to debug the Feather ESP32.
Debugging works great, but I run into the following issues:

1. If a breakpoint is hit, variables, watches breakpoints and registers are displayed, but the peripherals view always shows “No Information” for an ESP32. Is this not yet implemented?

2. Is there a way to set a watch on a variable directly in the IDE, such that execution stops when the variable is changed (Similar to execute “watch ” in the debug console?

3. If I define more than two breakpoints I get the following error message:

Warn : xtensa_add_breakpoint: max HW slot reached, slot=2
Info : Target halted. PRO_CPU: PC=0x400EBD1A             APP_CPU: PC=0x400916EE (active)
Info : Target halted. PRO_CPU: PC=0x400EBD1A             APP_CPU: PC=0x400D0ECE (active)
Target halted. PRO_CPU: PC=0x400EBD1A             APP_CPU: PC=0x400D0ECE (active)
Error: cpu0: xtensa_read_memory (line 700): DSR (8000CC19) indicates DIR instruction generated an overrun!
Warn : cpu0: Failed reading 18 bytes at address 0x400d0ebc
Info : Target halted. PRO_CPU: PC=0x400EBD1A             APP_CPU: PC=0x400916EE (active)

It looks like only hardware breakpoints are supported (max 2 available, see Tips and Quirks - ESP32 - — ESP-IDF Programming Guide latest documentation) if the code resides in flash, right? Or did I miss something here?

...OpenOCD: flash (up to 32) and IRAM (up to 32) breakpoints. Currently GDB can not set software breakpoints in flash. So until this limitation is removed those breakpoints have to be emulated by OpenOCD as hardware ones...

[maxgerhardt]

@erich

but the peripherals view always shows “No Information” for an ESP32

Because Espressif’s devs fail to create a proper SVD file which describes the ESP32’s hardware peripherirals. See thread at CLion Debugging for community-made workarounds and hacks.

@erich

Is there a way to set a watch on a variable directly in the IDE, such that execution stops when the variable is changed (Similar to execute "watch " in the debug console?

Those are called “Data breakpoints” and it seems a bit fuzzy to me how exactly VSCode supports them. Digging through initial VSCode issues like Debug Protocol: Data Breakpoints · Issue #38 · microsoft/vscode-debugadapter-node · GitHub they say that they have introduced data breakpoints, just like this blog post does. So does it work when you add variable names to the breakpoints?

You can also try to use native GDB commands directly in the “Debug Console”, see stackoverflow for watch (write), read and awatch (read/write) breakpoints for variables and memory addresses.

@erich

It looks like only hardware breakpoints are supported (max 2 available, see Tips and Quirks - ESP32 - — ESP-IDF Programming Guide latest documentation) if the code resides in flash, right?

Indeed, this is a limitation of the xtensa GDB which hasn’t been addressed by Espressif yet.

[erich]

@maxgerhardt

Because Espressif’s devs fail to create a proper SVD file which describes the ESP32’s hardware peripherirals. See thread at CLion Debugging for community-made workarounds and hacks.

The PR containing the required SVD seam to be in review. That’s good to know…

@maxgerhardt

Those are called “Data breakpoints” and it seems a bit fuzzy to me how exactly VSCode supports them. … So does it work when you add variable names to the breakpoints?

I don’t get the “Break when value changes” command in the context menu as described here Data Breakpoints. I’ll use watch for now, that’s fine.

@maxgerhardt

Indeed, this is a limitation of the xtensa GDB which hasn’t been addressed by Espressif yet

That’s out of the three the biggest limitation in my opinion…

Thanks for the quick reply!