.. _changelog_v3_5_0_beta_3:

v3.5.0-beta.3
=============

v3.5.0-beta.3 introduces **TensorFlow Lite for Microcontrollers**, integrates
**STM32Cube.AI** as a built-in module, and adds the **USSL / mbedTLS** module
for SSL/TLS. WINC1500 init now returns string errors and the YUV table was
disabled on the OpenMV 4 — read the breaking changes below. (This is a beta
leading up to :ref:`v3.5.0 <changelog_v3_5_0>`.)

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

Highlights
----------

- **TensorFlow Lite for Microcontrollers** — added (the start of the modern
  ``tf`` module).
- **STM32Cube.AI** — integrated as a built-in module with examples (X-CUBE-AI
  v4.1.0).
- **USSL / mbedTLS** — added the ``ussl`` MBEDTLS module for SSL/TLS.
- **Breaking:** WINC1500 init now returns string errors and the OpenMV 4 YUV
  table was disabled — see the breaking changes.

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

- **TensorFlow Lite for Microcontrollers** — added support for TFLite-micro
  models.
- **STM32Cube.AI** — integrated into the firmware as a built-in module, with
  updated MNIST / Cube.AI examples and X-CUBE-AI v4.1.0 support (Cube.AI files
  are now fetched separately per added instructions).
- **USSL** — enabled the ``ussl`` MBEDTLS module for SSL/TLS sockets, with
  updated WINC1500 HTTP/HTTPS client examples.

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

- Updated the WINC1500 firmware and host driver and socket buffer size;
  cleaned up the system clock config; enabled the SYSCFG clock before
  selecting VSCALE0 and switched to VSCALE1 before low-power mode.

Bug fixes
---------

Networking:

- WINC1500 now checks for an empty SSID and/or key.

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

- **OpenMV 4R** — uses QSPI for internal storage.

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

User-visible API breaks between v3.5.0-beta.2 and v3.5.0-beta.3. Scope: Python
C-modules in ``modules/`` and Python libraries in ``scripts/libraries/``.

Both breaking changes are *behavior* changes (same API, different results) —
re-check affected scripts. Each commit hash links to its diff on GitHub.

.. _v3_5_0_beta_3_winc:

WINC1500 init returns string errors *(behavior)*
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The WINC1500 ``init`` function now returns descriptive string errors instead
of numeric codes. Code that compared the WINC1500 init result against numeric
error values must be updated to handle the new string messages.

*Commits:* `15e0d455 <https://github.com/openmv/openmv/commit/15e0d455>`__

.. _v3_5_0_beta_3_yuv:

OpenMV 4 JPEG/grayscale output changed *(behavior)*
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The YUV lookup table was disabled on the OpenMV 4 / 4R, so JPEG and grayscale
output pixel values are computed slightly differently on those boards. Output
is still valid but differs marginally from prior releases; re-check
pixel-exact comparisons on the OpenMV 4.

*Commits:* `f9ed0cb82 <https://github.com/openmv/openmv/commit/f9ed0cb82>`__

.. _v3_5_0_beta_3_migration:

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

Handle string error returns from WINC1500 init
(:ref:`the WINC1500 change <v3_5_0_beta_3_winc>`) and re-check pixel-exact
comparisons on the OpenMV 4 (:ref:`the OpenMV 4 output change
<v3_5_0_beta_3_yuv>`). All other scripts run unchanged.