feat: add capture sketch, Vidor image tool and jitter analysis script

tools/vidor_image.py

@@ -0,0 +1,69 @@
+#!/usr/bin/env python3
+"""Turn a Quartus .ttf bitstream into the app image embedded in a MKR Vidor 4000 sketch.
+
+The Vidor bootloader expects the bitstream bytes bit-reversed relative to Quartus' .ttf
+output, written as a C initializer list (bitstream.h), plus a signature block (signature.h)
+describing where the image goes in the FPGA's flash. The app image slot starts at 512 KB.
+"""
+
+import argparse
+import hashlib
+from pathlib import Path
+
+APP_OFFSET_KB = 512
+IMAGE_TYPE_APP = 1
+
+
+def reverse_bits(byte: int) -> int:
+    return int(f"{byte:08b}"[::-1], 2)
+
+
+def read_ttf(path: Path) -> bytes:
+    values = (field.strip() for field in path.read_text().split(","))
+    return bytes(reverse_bits(int(v)) for v in values if v)
+
+
+def format_initializer(data: bytes) -> str:
+    lines = []
+    for start in range(0, len(data), 16):
+        chunk = data[start:start + 16]
+        if len(chunk) == 16:
+            lines.append(", ".join(f"{b:3d}" for b in chunk) + ",")
+        else:
+            lines.append("".join(f"{b:3d}, " for b in chunk))
+    return "\n".join(lines) + "\n"
+
+
+def hex_bytes(data: bytes) -> str:
+    return ", ".join(f"0x{b:02x}" for b in data) + ","
+
+
+def format_signature(image_text: str, length: int) -> str:
+    digest = hashlib.sha256(image_text.encode()).digest()
+    return "\n".join([
+        "NO_BOOTLOADER,",
+        hex_bytes((APP_OFFSET_KB * 1024).to_bytes(4, "little")),
+        hex_bytes(length.to_bytes(4, "little")),
+        hex_bytes(digest),
+        hex_bytes(IMAGE_TYPE_APP.to_bytes(4, "little")),
+        "0x00, 0x00, 0x00, 0x00, // force flag",
+        "NO_USER_DATA,",
+    ]) + "\n"
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("ttf", type=Path, help="Quartus .ttf bitstream")
+    parser.add_argument("out_dir", type=Path, help="directory for bitstream.h and signature.h")
+    args = parser.parse_args()
+
+    data = read_ttf(args.ttf)
+    image_text = format_initializer(data)
+    args.out_dir.mkdir(parents=True, exist_ok=True)
+    (args.out_dir / "bitstream.h").write_text(image_text)
+    (args.out_dir / "signature.h").write_text(format_signature(image_text, len(data)))
+    print(f"{len(data)} bytes -> {args.out_dir}/bitstream.h, signature.h")
+
+
+if __name__ == "__main__":
+    main()