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 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.

Highlights

  • OpenMV Cam Pure Thermal — new board support.

  • ~4× faster TensorFlow — tf inference now runs on CMSIS-NN.

  • 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

  • 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 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 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 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.

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

import sensor raises on sensor-less boards (behavior)

To support boards without an image sensor, the 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

Migration checklist

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