.. _changelog_v3_6_8:

v3.6.8
======

v3.6.8 adds the **OpenMV Cam Pure Thermal** board, makes ``tf`` inference
roughly **4× faster** by moving TensorFlow onto CMSIS-NN, expands the desktop
:mod:`rpc` library with UART / Kvaser CAN / I2C / SPI interfaces, and enables the
**SD card on the Arduino Portenta H7**. SD-card partition handling and
``import sensor`` on sensor-less boards changed — read the breaking changes
below.

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

Highlights
----------

- **OpenMV Cam Pure Thermal** — new board support.
- **~4× faster TensorFlow** — ``tf`` inference now runs on CMSIS-NN.
- :mod:`rpc` library — added UART, Kvaser CAN, and I2C/SPI master/slave
  interfaces.
- **Portenta H7 SD card** — SD card support enabled, with PLL1/HSE/ADC clock
  fixes.
- **Breaking:** SD-card boot now auto-detects the partition, and
  ``import sensor`` now raises when no image sensor is present — see the
  breaking changes.

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

- :mod:`rpc` — added UART, Kvaser CAN, and I2C/SPI master/slave interfaces to
  the desktop RPC library (``rpc_uart_master`` / ``rpc_uart_slave``,
  ``rpc_kvarser_can_master`` / ``rpc_kvarser_can_slave``, and I2C/SPI
  master/slave).
- **Sensor-less boards** — the firmware now supports boards without an image
  sensor (enabling the Pure Thermal board).
- **JPEG geometry** — added a JPEG read-settings struct (``jpg_w`` / ``jpg_h``
  / ``jpg_size``) for reading JPEG geometry.

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

- TensorFlow was switched to CMSIS-NN for roughly 4× faster ``tf`` inference
  (per-board imlib config adjusted); the :mod:`ulab` example uses
  ``ulab.numerical.mean`` / ``std``; the deep-sleep example now calls
  ``sensor.sleep(True)`` before the OV7725 regulator-bypass register write.

Bug fixes
---------

Camera and imaging:

- Fixed loading JPEG images from disk (JPEG geometry was rejected as an
  unsupported format), made :func:`sensor.reset` perform a hard reset so the
  sensor recovers after a regulator shutdown, corrected the FLIR Lepton SPI
  alternate-function / clock config on OpenMV 4 / 4 Plus, and fixed the FSYNC
  pin assignment on OpenMV 4 / 4 Plus.

Connectivity and system:

- Fixed the timed :class:`pyb.DAC` write on the H7, made WINC1500
  ``WLAN.start_ap()`` not require a key for OPEN security, fixed sharing the
  I2C bus between the camera and user peripherals on the Portenta, and made
  the self-test SWD framebuffer marker per-board so it no longer clobbers the
  framebuffer ``bpp`` on boards without it.

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

- **OpenMV Cam Pure Thermal** — new board.
- **Arduino Portenta H7** — SD card enabled, with PLL1 (400 MHz/40 MHz,
  USB/RNG on HSI48), HSE (25 MHz), and ADC clock-source fixes.

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

User-visible API breaks between v3.6.7 and v3.6.8. 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_6_8_sdpart:

SD-card partition auto-detection *(behavior)*
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

SD-card boot now auto-detects the partition instead of always mounting
partition 1. Cards that relied on the old fixed-partition-1 behavior may now
mount a different filesystem; re-check multi-partition SD cards and the
expected mount.

*Commits:* `1f7f003b8 <https://github.com/openmv/openmv/commit/1f7f003b8>`__

.. _v3_6_8_sensorimport:

``import sensor`` raises on sensor-less boards *(behavior)*
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To support boards without an image sensor, the :mod:`sensor` module's
initialization check now runs on import, so ``import sensor`` raises a
``RuntimeError`` when no image sensor is detected (instead of failing later).
On a thermal-only board, guard ``import sensor`` with ``try`` / ``except`` or
avoid importing it.

*Commits:* `17b444ad1 <https://github.com/openmv/openmv/commit/17b444ad1>`__

.. _v3_6_8_migration:

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

Re-check multi-partition SD cards against the new partition auto-detection
(:ref:`the SD-card change <v3_6_8_sdpart>`) and guard ``import sensor`` on
sensor-less / thermal-only boards (:ref:`the sensor-import change
<v3_6_8_sensorimport>`). All other scripts run unchanged.