v4.0.0

v4.0.0 is the major v3 → v4 release. It introduces the modern multi-frame sensor buffering API (double / triple buffering and a video FIFO), a frame complete callback, a Bluetooth module (NimBLE stack) with Portenta support, the initial MT9M114 camera driver, MDMA-offloaded camera capture, Bayer/JPEG support in image.draw_image(), and a jump to MicroPython 1.15. The legacy streaming mode was removed and sensor.set_windowing() was reworked — read the breaking changes below.

Highlights

  • Multi-frame buffering — sensor gains double buffering, triple buffering, and a video-FIFO mode for higher, smoother frame rates.

  • Frame complete callback — register a callback that fires when a new frame is ready, for non-blocking capture pipelines.

  • Bluetooth — a bluetooth module built on the NimBLE stack, enabled on the Arduino Portenta H7 (with a BLE example).

  • MT9M114 — initial camera sensor driver.

  • Faster capture — MDMA offload for camera data capture; draw_image() now accepts Bayer and JPEG sources/destinations.

  • MicroPython 1.15 — the bundled MicroPython was updated from 1.13 to 1.15.

  • Breaking: the legacy streaming mode was removed and sensor.set_windowing() was reworked — see the breaking changes.

New features

  • Sensor multi-buffering — added sensor.set_framebuffers() / sensor.get_framebuffers() and the SINGLE_BUFFER / DOUBLE_BUFFER / TRIPLE_BUFFER / VIDEO_FIFO modes, plus sensor.get_frame_available() for double, triple, and video-FIFO capture.

  • Frame complete callback — added sensor.set_frame_callback() so a Python callback runs when each new frame finishes.

  • Bluetooth — added a bluetooth module backed by the NimBLE stack (NimBLE submodule, CYW-BT driver), enabled on the Arduino Portenta H7 with a BLE example.

  • MT9M114 — added the initial MT9M114 camera sensor driver.

  • draw_image — added debayering support and JPEG copy support so image.draw_image() accepts Bayer and JPEG source/destination images.

  • MDMA capture offload — camera data capture is offloaded to MDMA for higher throughput.

  • A color-palette argument can now be disabled by passing -1 (since None is reserved as a valid argument).

Other changes and improvements

  • Switched to the new software I2C implementation; aligned with MicroPython upstream; per-board ulab configuration; basic built-in modules enabled for OpenMV 2; fairer frame-buffer readout locking; mutex support extended to Cortex-M0/M0+ with a lock timeout.

Bug fixes

Camera and imaging:

  • Fixed FLIR Lepton init reliability on the Pure Thermal board, ImageIO JPEG buffer / pause handling, HM01B0 vflip/hmirror settings, the JPEG buffer flush when an image is invalidated, and a cropped flag that was set when the framesize was invalid.

System and connectivity:

  • Fixed the USB command draining and the reset-to-bootloader command, mutex init, the UART clock source, the FatFS code-page define, WINC1500 out-of-band ACK handling, WiFi debugging, and the Nano33 USB PID; isolated dedicated analog pads.

Hardware and board support

  • MT9M114 camera sensor (initial driver).

  • Arduino Portenta H7 — Bluetooth enabled (NimBLE) with a BLE example.

  • Arduino Nano RP2040 Connect / Nano 33 BLE Sense — WiFi-debug flag disabled where unsupported; blinky example added; USB PID fix.

Breaking API changes

User-visible API breaks between v3.9.4 and v4.0.0. Scope: Python C-modules in modules/ and Python libraries in scripts/libraries/.

Each change is tagged with its impact:

  • major — affects most scripts; you will almost certainly need to port code.

  • minor — narrow API; only affects scripts that used it.

  • behavior — same API, different results; re-check tuned scripts.

Changes are grouped by impact in that order. If you just want to port your code, jump to the migration checklist at the end. Each commit hash links to its diff on GitHub.

Streaming mode removed (major)

The legacy sensor streaming mode was removed in favor of the new multi-frame buffering API. Code that enabled streaming mode must switch to sensor.set_framebuffers() with DOUBLE_BUFFER / TRIPLE_BUFFER / VIDEO_FIFO and drive capture with sensor.snapshot() / sensor.get_frame_available() instead.

Commits: a42f3a647

sensor.set_windowing() reworked (behavior)

sensor.set_windowing() was made much more flexible: it now accepts multiple argument forms (a region tuple, or width/height centered, or x, y, w, h) and resolves the window relative to the current resolution. Scripts that passed windowing arguments in the old fixed form may select a different region and should be re-checked.

Commits: 3e9c43554

MicroPython 1.13 → 1.15 (behavior)

The bundled MicroPython core was updated from 1.13 to 1.15 (via 1.14). Standard-library and language behavior follows upstream MicroPython 1.15; re-check scripts that depend on version-specific micropython / standard module behavior.

Commits: 364eea6c7, 26c5376b0

ImageIO update_jpeg_buffer argument removed (minor)

The ImageIO JPEG-buffer update was reworked to derive the buffer from the image source argument, and the explicit update_jpeg_buffer argument was removed. Scripts that passed update_jpeg_buffer to ImageIO must drop that argument.

Commits: 5c6937bd1

Migration checklist

For a clean port to v4.0.0 the typical work is:

  1. Replace any use of the removed streaming mode with the new sensor.set_framebuffers() multi-buffering API (streaming mode removed).

  2. Re-check sensor.set_windowing() calls against the reworked, more flexible argument handling (the windowing change).

  3. Re-validate scripts that depend on version-specific MicroPython behavior against MicroPython 1.15 (the MicroPython bump).

  4. Drop the update_jpeg_buffer argument from ImageIO calls (the ImageIO change).

All other scripts run unchanged.