I have a Tronxy X5SA printer upon which I want to install the latest Marlin firmware v2.0.9.1.

I take the configuration example on GitHub for the X5SA printer and modify the lines in configuration.h as recommended in the guide (see this URL).

In Visual Studio Code, when I compile, I obtain this error :

Marlin\src\gcode\motion\G2_G3.cpp: In function 'void plan_arc(const xyze_pos_t&, const ab_float_t&, bool, uint8_t)':
Marlin\src\gcode\motion\G2_G3.cpp:154:7: error: 'MM_PER_ARC_SEGMENT' was not declared in this scope
Marlin\src\gcode\motion\G2_G3.cpp:154:7: note: suggested alternative: 'MAX_ARC_SEGMENT_MM'
Compiling .pio\build\chitu_f103\src\src\gcode\sd\M20.cpp.o
*** [.pio\build\chitu_f103\src\src\gcode\motion\G2_G3.cpp.o] Error 1
========================================================================================= [FAILED] Took 71.95 seconds ========================================================================================= 

Environment    Status    Duration
-------------  --------  ------------
chitu_f103     FAILED    00:01:11.945
==================================================================================== 1 failed, 0 succeeded in 00:01:11.945 ==================================================================================== 
PS D:\TRONXY\Marlin-\Marlin-> echo "done" >C:\Users\myUser\AppData\Local\Temp\ipc
PS D:\TRONXY\Marlin-\Marlin-> 

Here is the code in G2_G3.cpp on line 154, but I need some help to understand why it's wrong, and how to fix...

 // Start with a nominal segment length
  float seg_length = (
  // Divide total travel by nominal segment length
  uint16_t segments = FLOOR(mm_of_travel / seg_length);
  NOLESS(segments, min_segments);         // At least some segments
  seg_length = mm_of_travel / segments;

I have tried to compile the BugFix version successfully, but unfortunately the bugfix version does not work properly with my printer (I can't get the bed to lift to the probe. I have opened another post for the bugfix version issue).


1 Answer 1


The compiler can't see the definition of MM_PER_ARC_SEGMENT. Find the file that it is declared in and ensure that file in included in the compile command, as an include (#include) or path or whatever.

Looking at the current Configuration_adv.h on the Marlin Github repository, the definition is at Line 2033 in the section at Lines 2028-2041

// G2/G3 Arc Support
#define ARC_SUPPORT                 // Disable this feature to save ~3226 bytes
  #define MM_PER_ARC_SEGMENT      1 // (mm) Length (or minimum length) of each arc segment
  //#define ARC_SEGMENTS_PER_R    1 // Max segment length, MM_PER = Min
  #define MIN_ARC_SEGMENTS       24 // Minimum number of segments in a complete circle
  //#define ARC_SEGMENTS_PER_SEC 50 // Use feedrate to choose segment length (with MM_PER_ARC_SEGMENT as the minimum)
  #define N_ARC_CORRECTION       25 // Number of interpolated segments between corrections
  //#define ARC_P_CIRCLES           // Enable the 'P' parameter to specify complete circles
  //#define CNC_WORKSPACE_PLANES    // Allow G2/G3 to operate in XY, ZX, or YZ planes
  //#define SF_ARC_FIX              // Enable only if using SkeinForge with "Arc Point" fillet procedure

Ensure that you have ARC_SUPPORT enabled - do not have the following line (2031) commented out:

#define ARC_SUPPORT 

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