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 v3.5.0.)

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.

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

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

Migration checklist

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