Add second upload method through native USB Port for SAM-based boards

platformio/boards/arduino.json

@@ -620,5 +620,31 @@
             "use_1200bps_touch": true,
             "wait_for_upload_port": true
         }
+    },
+    "dueUSB": {
+        "build": {
+            "core": "arduino",
+            "extra_flags": "-D__SAM3X8E__ -DARDUINO_SAM_DUE -DARDUINO_ARCH_SAM",
+            "f_cpu": "84000000L",
+            "mcu": "at91sam3x8e",
+            "cpu": "cortex-m3",
+            "pid": "0x003e",
+            "usb_product": "Arduino Due",
+            "variant": "arduino_due_x",
+            "vid": "0x2341",
+            "ldscript": "sam3x8e.ld"
+        },
+        "framework": "arduino",
+        "name": "Arduino Due (USB Native Port)",
+        "platform": "atmelsam",
+        "upload": {
+            "disable_flushing": true,
+            "maximum_ram_size": 28672,
+            "maximum_size": 524288,
+            "protocol": "sam-ba",
+            "require_upload_port" : true, 
+            "use_1200bps_touch": true,
+            "wait_for_upload_port": true
+        }
     }
 }

platformio/builder/scripts/atmelsam.py

@@ -10,10 +10,33 @@ from os.path import join
 from SCons.Script import (COMMAND_LINE_TARGETS, AlwaysBuild, Default,
                           DefaultEnvironment, SConscript)
 
+from platformio.util import get_serialports
+
 
 def BeforeUpload(target, source, env):  # pylint: disable=W0613,W0621
     env.AutodetectUploadPort()
 
+    board_type = env.subst("$BOARD")
+    env.Append(
+        UPLOADERFLAGS=[
+            "-U",
+            "true" if "usb" in board_type.lower(
+            ) or board_type == "digix" else "false"
+        ])
+
+    upload_options = env.get("BOARD_OPTIONS", {}).get("upload", {})
+
+    if not upload_options.get("disable_flushing", False):
+        env.FlushSerialBuffer("$UPLOAD_PORT")
+
+    before_ports = [i['port'] for i in get_serialports()]
+
+    if upload_options.get("use_1200bps_touch", False):
+        env.TouchSerialPort("$UPLOAD_PORT", 1200)
+
+    if upload_options.get("wait_for_upload_port", False):
+        env.Replace(UPLOAD_PORT=env.WaitForNewSerialPort(before_ports))
+
 
 env = DefaultEnvironment()