v4.3.0#

v4.3.0 adds hardware-accelerated JPEG decoding, FLIR Lepton high-temperature mode and model detection, new JPEG color-space conversions, and MicroPython 1.18, plus a batch of RTC and WiFi fixes. The Lepton measurement-mode API changed — read the breaking changes below.

Highlights#

  • Hardware JPEG decoding on STM32 (H7) — faster JPEG decompression.

  • FLIR Lepton high-temperature mode (up to ~600 °C on Lepton 3.5) and automatic model detection (1.5–3.5).

  • New JPEG conversions — decode YCbCr JPEGs to grayscale and grayscale JPEGs to RGB565.

  • MicroPython updated to 1.18.

  • Breaking: the Lepton measurement-mode ioctl changed — see the breaking changes.

New features#

  • Hardware-accelerated JPEG decoding — the STM32 on-chip JPEG codec is now used for decompression.

  • JPEG color-space conversions — the decoder can decode YCbCr JPEGs to GRAYSCALE and GRAYSCALE JPEGs to RGB565.

  • Lepton high-temperature mode — a new high_temp measurement mode uses low-gain to extend the range to roughly 600 °C on the Lepton 3.5.

  • Arduino Nano RP2040 Connect — the onewire, dht, and neopixel driver modules are now frozen into the firmware.

Other changes and improvements#

  • MicroPython updated to 1.18.

  • The FLIR Lepton driver now detects and reports the specific Lepton model (1.5 / 1.6 / 2.0 / 2.5 / 3.0 / 3.5) to the IDE.

Bug fixes#

Image processing:

  • Image.to_grayscale() / L-channel conversion no longer returns negative L values for dark RGB565 pixels; the JPEG decoder no longer faults (MemManage) on odd-dimension images.

Camera and sensors:

  • Fixed GC2145 window subsampling ratios and Bayer pixel order for correct image quality at sub-QVGA resolutions and in BAYER mode.

Networking and storage:

  • Corrected WINC1500 non-blocking socket timeout handling and added proper MicroPython errno mapping for socket errors; fixed the STM32 OpenMV USB-disk file handling.

Real-time clock:

  • Fixed the RTC clock source / LSE-vs-LSI selection and LSE oscillator errata across the OpenMV Cam H7 Plus and Pure Thermal boards.

Hardware and board support#

  • STM32 (H7) — hardware JPEG decoding.

  • OpenMV Cam H7 Plus / Pure Thermal — RTC clock-source fixes.

  • Arduino Nano RP2040 Connect — frozen onewire / dht / neopixel drivers.

Breaking API changes#

User-visible API breaks between v4.2.3 and v4.3.0. Scope: Python C-modules in modules/ and Python libraries in scripts/libraries/.

Each change is tagged with its impact:

  • minor — narrow API; only affects scripts that used it.

  • behavior — same API, different results; re-check tuned scripts.

Both breaking changes affect the FLIR Lepton thermal sensor only. Each commit hash links to its diff on GitHub.

Lepton measurement-mode ioctl (minor)#

sensor.ioctl(SET_MEASUREMENT_MODE, ...) accepts a new optional high_temp argument, and GET_MEASUREMENT_MODE now returns a 2-tuple (enabled, high_temp) instead of a single boolean. Code that read the previous boolean return value must be updated to unpack the tuple.

Commit: 6b2cd1008

Lepton default temperature range (behavior)#

The FLIR Lepton default temperature range changed from −17.78 °C…37.78 °C to −10.0 °C…40.0 °C. The color mapping and reported temperatures for scenes that relied on the old default range will differ — set an explicit range if you need the previous behavior.

Commit: bc07e0131

Migration checklist#

Only FLIR Lepton scripts are affected: unpack the new GET_MEASUREMENT_MODE (enabled, high_temp) tuple (the measurement-mode change) and set an explicit temperature range if you depended on the old default (the default-range change). All other scripts run unchanged.