.. _changelog_v3_6_5:

v3.6.5
======

v3.6.5 updates TensorFlow and :mod:`ulab`, substantially improves the **HM01B0**
camera (arbitrary resolutions, QQVGA, cropping, ``set_auto_exposure()``, and
an anti-flicker fix), and brings Portenta external-SDRAM and production board
support. The legacy CMSIS-NN training tooling/examples were removed and the
OpenMV 4 Plus framebuffer was reduced — read the breaking changes below.

.. contents:: On this page
   :local:
   :depth: 1

Highlights
----------

- **HM01B0** — arbitrary resolutions, QQVGA, cropping, and ``set_auto_exposure()``
  support, plus an automatic-exposure flicker fix.
- **TensorFlow / ulab** updated to their latest versions.
- **Portenta** — external-SDRAM usage and production board files.
- **Fixes** — lens correction, image quality at low resolutions, and an FPS
  clock fix.
- **Breaking:** the legacy CMSIS-NN training/conversion tooling and examples
  were removed and the OpenMV 4 Plus framebuffer was reduced — see the
  breaking changes.

New features
------------

- **HM01B0** — added arbitrary-resolution support, QQVGA and additional
  stubs, sensor-side cropping, and :func:`sensor.set_auto_exposure` support.
- **Apriltag readout** — added a readout-control apriltag-tracking example.

Other changes and improvements
------------------------------

- Updated TensorFlow and :mod:`ulab` to their latest versions; added Portenta
  external-SDRAM usage and production/CI board files; cleaned up the
  MT9V034 driver and the framebuffer accessor functions.

Bug fixes
---------

Camera and imaging:

- Fixed flickering during automatic exposure on the HM01B0, lens correction,
  image quality at lower resolutions, the OV5640/JPEG line copy
  (``dest_fb``), the FPS clock, and returning 0 when ``bpp`` is negative;
  removed an unnecessary HM01B0 horizontal flip.

Hardware and board support
--------------------------

- **HM01B0** — arbitrary resolutions, QQVGA, and cropping.
- **Arduino Portenta H7** — external SDRAM and updated production board
  files.

Breaking API changes
--------------------

User-visible API breaks between v3.6.4 and v3.6.5. Scope: Python C-modules in
``modules/``, Python libraries in ``scripts/libraries/``, and the bundled
tooling/examples.

Each change is tagged with its impact:

- *behavior* — same API, different results; re-check tuned scripts.
- *tooling* — affects the build/conversion tooling or bundled examples, not
  the firmware Python API.

Changes are grouped by impact in that order. If you just want to port your
code, jump to the :ref:`migration checklist <v3_6_5_migration>` at the end.
Each commit hash links to its diff on GitHub.

.. _v3_6_5_fb:

OpenMV 4 Plus framebuffer reduced *(behavior)*
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The OpenMV 4 Plus framebuffer was reduced to 20 MB (and the OpenMV 2/3 buffer
size was corrected). Memory-tight scripts on the OpenMV 4 Plus that allocated
very large frames/objects from the framebuffer may now hit allocation limits
sooner and should be re-checked.

*Commits:* `3a790a827 <https://github.com/openmv/openmv/commit/3a790a827>`__

.. _v3_6_5_cmsisnn:

Legacy CMSIS-NN tooling and examples removed *(tooling)*
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The legacy CMSIS-NN model-training/conversion tooling (``nn_convert.py``,
``nn_quantizer.py``, the LeNet/CIFAR/smile model files) and the
``25-Machine-Learning/nn_*.py`` example scripts were removed. The ``nn``
module itself still works in this release (it is removed later, in v3.9.0),
but the CMSIS-NN model-generation tooling is gone — use the TensorFlow Lite
(``tf``) workflow instead.

*Commits:* `588f79a62 <https://github.com/openmv/openmv/commit/588f79a62>`__

.. _v3_6_5_migration:

Migration checklist
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Re-check large framebuffer allocations on the OpenMV 4 Plus against the
reduced 20 MB framebuffer (:ref:`the framebuffer change <v3_6_5_fb>`), and
move CMSIS-NN model generation to the TensorFlow Lite workflow
(:ref:`the CMSIS-NN tooling removal <v3_6_5_cmsisnn>`). All other scripts run
unchanged.