Add end-to-end USB flashing for the app firmware via UF2

Adds uf2conv.py (minimal, dependency-free .bin -> .uf2 converter matching bootloader/inc/uf2format.h's block layout) and upload_uf2.py, a PlatformIO upload hook for env:versapad_usb that finds the mounted VERSABOOT volume and copies the converted firmware onto it. env:versapad_usb previously used upload_protocol=sam-ba, the classic Arduino/Atmel protocol -- the actual bootloader speaks UF2/mass storage, not SAM-BA, so that upload path never worked. Switched to upload_protocol=custom with the new hook, and cleaned the now-unused SAM-BA-specific fields out of boards/versapad.json. Verified end to end on real hardware: pio run -e versapad_usb --target upload builds, converts, copies to the VERSABOOT drive, and the bootloader jumps into the freshly written app on its own. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-08-05 21:35:19 +02:00 · 2026-08-05 21:35:19 +02:00 · d325297063
commit d325297063
parent f60a29137c
7 changed files with 210 additions and 32 deletions
--- a/upload_uf2.py
+++ b/upload_uf2.py
@ -0,0 +1,72 @@
+"""PlatformIO upload hook for env:versapad_usb.
+
+The board's actual bootloader (bootloader/, UF2/mass-storage) does not speak
+SAM-BA, so upload_protocol=sam-ba (the board.json default, inherited from an
+Arduino-Zero-style template) does not work here. This converts the built
+.bin to .uf2 and copies it onto the VERSABOOT mass-storage volume instead --
+Windows only for now, matching the rest of this project's dev environment.
+"""
+import ctypes
+import os
+import string
+import sys
+
+Import("env")
+
+sys.path.insert(0, env.subst("$PROJECT_DIR"))
+import uf2conv
+
+VOLUME_LABEL = "VERSABOOT"
+DRIVE_UNKNOWN = 0
+DRIVE_NO_ROOT_DIR = 1
+
+
+def find_versaboot_drive(label=VOLUME_LABEL):
+    for letter in string.ascii_uppercase:
+        root = f"{letter}:\\"
+        drive_type = ctypes.windll.kernel32.GetDriveTypeW(root)
+        if drive_type in (DRIVE_UNKNOWN, DRIVE_NO_ROOT_DIR):
+            continue
+        vol_name_buf = ctypes.create_unicode_buffer(261)
+        fs_name_buf = ctypes.create_unicode_buffer(261)
+        ok = ctypes.windll.kernel32.GetVolumeInformationW(
+            ctypes.c_wchar_p(root),
+            vol_name_buf,
+            ctypes.sizeof(vol_name_buf),
+            None,
+            None,
+            None,
+            fs_name_buf,
+            ctypes.sizeof(fs_name_buf),
+        )
+        if ok and vol_name_buf.value == label:
+            return root
+    return None
+
+
+def upload_via_uf2(source, target, env):
+    build_dir = env.subst("$BUILD_DIR")
+    bin_path = os.path.join(build_dir, "firmware.bin")
+    uf2_path = os.path.join(build_dir, "firmware.uf2")
+
+    if not os.path.isfile(bin_path):
+        print(f"error: {bin_path} not found (expected as a normal build product)")
+        env.Exit(1)
+
+    num_blocks = uf2conv.convert(bin_path, uf2_path, base_addr=0x2000, family_id=uf2conv.SAMD21_FAMILY_ID)
+    print(f"Wrote {uf2_path}: {num_blocks} blocks")
+
+    drive = find_versaboot_drive()
+    if drive is None:
+        print(f"error: no drive labeled '{VOLUME_LABEL}' found.")
+        print("Hold the bottom-right Cherry MX key while plugging in USB to enter the bootloader.")
+        env.Exit(1)
+
+    dest = os.path.join(drive, "firmware.uf2")
+    print(f"Copying {uf2_path} -> {dest}")
+    with open(uf2_path, "rb") as src, open(dest, "wb") as dst:
+        dst.write(src.read())
+    print("Upload triggers a reset into the app on the device side; no further action needed.")
+
+
+env.Replace(UPLOADCMD=upload_via_uf2)