Fysetc S6 support (#15850)

platformio.ini

@@ -395,6 +395,28 @@ lib_ignore    = Adafruit NeoPixel, TMCStepper
 src_filter    = ${common.default_src_filter} +<src/HAL/HAL_STM32_F4_F7> -<src/HAL/HAL_STM32_F4_F7/STM32F7>
 monitor_speed = 250000
 
+#
+# FYSETC S6 (STM32F446VET6 ARM Cortex-M4)
+#
+[env:FYSETC_S6]
+platform          = ststm32
+framework         = arduino
+board             = fysetc_s6
+extra_scripts     = buildroot/share/PlatformIO/scripts/fysetc_STM32S6.py
+build_flags       = ${common.build_flags}
+  -DTARGET_STM32F4 -std=gnu++14
+  -DVECT_TAB_OFFSET=0x10000
+  -DUSBCON -DUSBD_USE_CDC -DHAL_PCD_MODULE_ENABLED -DUSBD_VID=0x0483 '-DUSB_PRODUCT="FYSETC_S6"'
+build_unflags     = -std=gnu++11
+lib_deps          = ${common.lib_deps}
+lib_ignore        = Arduino-L6470
+src_filter        = ${common.default_src_filter} +<src/HAL/HAL_STM32>
+monitor_speed     = 250000
+platform_packages = tool-stm32duino
+debug_tool        = stlink
+#upload_protocol   = stlink
+upload_protocol   = serial
+
 #
 # STM32F7 with STM32GENERIC
 #
@@ -412,7 +434,7 @@ monitor_speed = 250000
 # ARMED (STM32)
 #
 [env:ARMED]
-platform      = ststm32@>=5.7.0
+platform      = ststm32
 framework     = arduino
 board         = armed_v1
 build_flags   = ${common.build_flags}
@@ -523,7 +545,7 @@ monitor_speed = 250000
 # Shield - https://github.com/jmz52/Hardware
 #
 [env:STM32F407VE_black]
-platform          = ststm32@>=5.7.0
+platform          = ststm32
 framework         = arduino
 platform_packages = framework-arduinoststm32@>=3.10700.191028
 board             = blackSTM32F407VET6
@@ -541,7 +563,7 @@ monitor_speed     = 250000
 # Bigtreetech SKR Pro (STM32F407ZGT6 ARM Cortex-M4)
 #
 [env:BIGTREE_SKR_PRO]
-platform          = ststm32@>=5.7.0
+platform          = ststm32
 framework         = arduino
 platform_packages = framework-arduinoststm32@>=3.10700.191028
 board             = BigTree_SKR_Pro
@@ -600,7 +622,7 @@ monitor_speed = 250000
 # Malyan M200 (STM32F103CB)
 #
 [env:STM32F103CB_malyan]
-platform    = ststm32@>=5.7.0
+platform    = ststm32
 framework   = arduino
 board       = malyanM200
 build_flags = !python Marlin/src/HAL/HAL_STM32F1/build_flags.py -DMCU_STM32F103CB -D __STM32F1__=1 -std=c++1y -D MOTHERBOARD="BOARD_MALYAN_M200" -DSERIAL_USB -ffunction-sections -fdata-sections -Wl,--gc-sections