Switch BTT SKR mini boards to STM32 HAL by default

Starting from 2.0.9 the STM32 is a default HAL for STM32F103 SoCs.
Due to space saving constrains with new HAL the volumetric commands
are disabled (they don't make much sense on MZ printers anyway).

Older STM32F1 HAL is available for targets marked "btt_mini_maple"

Author: kad

Marlin/Configuration_adv.h

@@ -3661,9 +3661,9 @@
 /**
  * Disable all Volumetric extrusion options
  */
-#if DISABLED(KAD_SKR_ENOUGH_FLASH)
-  #define NO_VOLUMETRICS
-#endif
+//#if DISABLED(KAD_SKR_ENOUGH_FLASH)
+#define NO_VOLUMETRICS
+//#endif
 
 #if DISABLED(NO_VOLUMETRICS)
   /**

anycubic_mega_zero2_btt_skr_mini.ini

@@ -8,19 +8,26 @@
 #
 # Build targets:
 #
-# BigTreeTech SKR mini MZ or SKR mini E3 V2.0, 24 Volt, Nanolib, Heated Bed
+# BigTreeTech SKR mini MZ or SKR mini E3 V2.0, 24 Volt, Heated bed
+# anycubic_mega_zero2_btt_mini       -- New STM32 HAL. Default since 2.0.9.1
+# anycubic_mega_zero2_btt_mini_maple -- Older, pre-2.0.9 STM32F1 HAL
 #
-# anycubic_mega_zero2_btt_mini              Manual Mesh Bed Leveling
-# anycubic_mega_zero2_btt_mini_bl           Automatic bed leveling, BLTouch is connected to PROBE port
-# anycubic_mega_zero2_btt_mini_e0fan        Same as anycubic_mega_zero_btt_mini but FAN1 is used for extruder cooling.
-# anycubic_mega_zero2_btt_mini_bl_e0fan     Same as anycubic_mega_zero_btt_mini_bl but FAN1 is used for extruder cooling.
-#
-# Standard Library, base configs for debug purposes
-#
-# anycubic_mega_zero2_btt_stdlib            Manual Mesh Bed Leveling
-# anycubic_mega_zero2_btt_stdlib_bl         Automatic bed leveling, BLTouch is connected to PROBE port
-# anycubic_mega_zero2_btt_stdlib_e0fan      Same as anycubic_mega_zero2_btt_stdlib but FAN1 is used for extruder cooling.
-# anycubic_mega_zero2_btt_stdlib_bl_e0fan   Same as anycubic_mega_zero2_btt_stdlib_bl but FAN1 is used for extruder cooling.
+# Default features in base build:
+# - Heated bed
+# - Full menus
+# - Mesh Bed Leveling (manual)
+# - Smart Filament Sensor (compiled in, not turend on by default)
+# - Power control
+# - CNC_FAN2 is configured as automatic "Controller Fan": switches on when motors are active.
+
+# Additional features in build variants (suffixes meanings):
+# - bl        -- Automatic bed leveling, BLTouch is connected to PROBE port
+# - bl_zmin   -- Automatic bed leveling, BLTouch is connected to PROBE port (servo) + Zmin (sensor)
+# - bfpt      -- Similar to "bl", but with DIY sensor with sensor and optical endstop.
+# - bfpt_zmin -- Similar to "bl_zmin", for DIY sensor.
+# - e0fan     -- CNC_FAN2 is used as automatic hotend Fan. Switches on when hotend is above 50ºC
+# - fs        -- Simple filament sensor instead of default "Smart Filament Sensor" (motion)
+# - pinda     -- Automatic bed leveling with inductive sensor connected to PROBE port
 #
 
 [env:anycubic_mega_zero2_btt_mini]
@@ -53,6 +60,12 @@ extends       = env:anycubic_mega_zero2_btt_mini
 [env:anycubic_mega_zero2_btt_mini_bl_zmin_e0fan]
 extends       = env:anycubic_mega_zero2_btt_mini
 
+[env:anycubic_mega_zero2_btt_mini_akp]
+extends       = env:anycubic_mega_zero_btt_mini
+
+[env:anycubic_mega_zero2_btt_mini_akp_e0fan]
+extends       = env:anycubic_mega_zero_btt_mini
+
 [env:anycubic_mega_zero2_btt_mini_bfpt]
 extends       = env:anycubic_mega_zero_btt_mini
 
@@ -71,20 +84,57 @@ extends       = env:anycubic_mega_zero_btt_mini
 [env:anycubic_mega_zero2_btt_mini_pinda_e0fan]
 extends       = env:anycubic_mega_zero_btt_mini
 
-[env:anycubic_mega_zero2_btt_stdlib]
-extends       = env:anycubic_mega_zero_btt_stdlib
+# MAPLE old-compatibility HAL
+[env:anycubic_mega_zero2_btt_mini_maple]
+extends       = env:anycubic_mega_zero_btt_mini_maple
+
+[env:anycubic_mega_zero2_btt_mini_maple_fs]
+extends       = env:anycubic_mega_zero_btt_mini_maple
+
+[env:anycubic_mega_zero2_btt_mini_maple_e0fan]
+extends       = env:anycubic_mega_zero2_btt_mini_maple
+
+[env:anycubic_mega_zero2_btt_mini_maple_e0fan_fs]
+extends       = env:anycubic_mega_zero2_btt_mini_maple
+
+[env:anycubic_mega_zero2_btt_mini_maple_bl]
+extends       = env:anycubic_mega_zero2_btt_mini_maple
+
+[env:anycubic_mega_zero2_btt_mini_maple_bl_fs]
+extends       = env:anycubic_mega_zero2_btt_mini_maple
+
+[env:anycubic_mega_zero2_btt_mini_maple_bl_zmin]
+extends       = env:anycubic_mega_zero2_btt_mini_maple
+
+[env:anycubic_mega_zero2_btt_mini_maple_bl_e0fan]
+extends       = env:anycubic_mega_zero2_btt_mini_maple
+
+[env:anycubic_mega_zero2_btt_mini_maple_bl_e0fan_fs]
+extends       = env:anycubic_mega_zero2_btt_mini_maple
+
+[env:anycubic_mega_zero2_btt_mini_maple_bl_zmin_e0fan]
+extends       = env:anycubic_mega_zero2_btt_mini_maple
+
+[env:anycubic_mega_zero2_btt_mini_maple_akp]
+extends       = env:anycubic_mega_zero_btt_mini_maple
+
+[env:anycubic_mega_zero2_btt_mini_maple_akp_e0fan]
+extends       = env:anycubic_mega_zero_btt_mini_maple
+
+[env:anycubic_mega_zero2_btt_mini_maple_bfpt]
+extends       = env:anycubic_mega_zero_btt_mini_maple
 
-[env:anycubic_mega_zero2_btt_stdlib_e0fan]
-extends       = env:anycubic_mega_zero2_btt_stdlib
+[env:anycubic_mega_zero2_btt_mini_maple_bfpt_e0fan]
+extends       = env:anycubic_mega_zero_btt_mini_maple
 
-[env:anycubic_mega_zero2_btt_stdlib_bl]
-extends       = env:anycubic_mega_zero2_btt_stdlib
+[env:anycubic_mega_zero2_btt_mini_maple_bfpt_zmin]
+extends       = env:anycubic_mega_zero_btt_mini_maple
 
-[env:anycubic_mega_zero2_btt_stdlib_bl_zmin]
-extends       = env:anycubic_mega_zero2_btt_stdlib
+[env:anycubic_mega_zero2_btt_mini_maple_bfpt_zmin_e0fan]
+extends       = env:anycubic_mega_zero_btt_mini_maple
 
-[env:anycubic_mega_zero2_btt_stdlib_bl_e0fan]
-extends       = env:anycubic_mega_zero2_btt_stdlib
+[env:anycubic_mega_zero2_btt_mini_maple_pinda]
+extends       = env:anycubic_mega_zero_btt_mini_maple
 
-[env:anycubic_mega_zero2_btt_stdlib_bl_zmin_e0fan]
-extends       = env:anycubic_mega_zero2_btt_stdlib
+[env:anycubic_mega_zero2_btt_mini_maple_pinda_e0fan]
+extends       = env:anycubic_mega_zero_btt_mini_maple