Summary: This repository holds the initial Zephyr RTOS app that demonstrates functional and interactive LEDs, user button, camera, display, alongside the "hello world" tflite-micro sample (sine wave prediction) running.

Camera + display app with a TensorFlow Lite Micro (TFLM) hello_world sine model overlay on the camera frame.

The overlay is drawn using the Zephyr hello_world tflite-micro model: for each x in [0, 2π], the app runs TFLM inference and draws the predicted y (sine) on the camera image in green.

The app requires the tflite-micro Zephyr module. From your Zephyr workspace (parent of this app), run:

west config manifest.project-filter -- +tflite-micro
west update

Then build from this directory or pass it to west build:

west build -b <your_board> -- -DBOARD_ROOT=$(pwd)
# or, if this app is under your workspace:
west build -b <your_board> kk_edge_ai_tflm_hello

• Display (chosen via zephyr,display)
• Camera (OV5640 + DCMI, chosen via zephyr,camera)
• Button (sw0) to start capture

Press Button 2 to start camera capture; the TFLM sine wave is overlaid on each frame.

Logging runs in deferred mode: callers (e.g. LOG_INF) only enqueue messages; a dedicated low-priority logging thread does formatting and output. This keeps log I/O out of time-critical paths (camera, display, inference). Configured via CONFIG_LOG_MODE_DEFERRED=y and CONFIG_LOG_BUFFER_SIZE=2048 in prj.conf.

To offload UART TX (and RX) to DMA and reduce CPU load:

1. Ensure CONFIG_DMA=y and CONFIG_UART_STM32_DMA=y in prj.conf (already set).
2. Build with the optional overlay so the console UART has DMA channels in devicetree:

   west build -b <board> -- -DOVERLAY_FILE=uart_dma.overlay

3. The provided uart_dma.overlay targets USART1 (e.g. B-U585I-IOT02A). If your board uses another UART for console (e.g. lpuart1), edit the overlay: change the node (e.g. &lpuart1) and the DMA request slots to match your SoC (see the STM32U5 Reference Manual for GPDMA request mapping).