framebuffer-dump

# Framebuffer Dump (J-Link → PNG) Export the **actual on-device rendered frame** directly from SDRAM framebuffer and convert to PNG. ## Default parameters (PRO2) - Device: `STM32H747XI_M7` - FB base: `0xD0000000` - Resolution: `604x1024` - Pixel format: `RGB888` (3 bytes/pixel) - Dump size: `604*1024*3 = 1,855,488 (0x1C5000)` ## One-shot workflow ### 1) Create J-Link command file Use `scripts/dump_fb.jlink.template` and replace placeholders: - `{{DEVICE}}` - `{{SPEED_KHZ}}` (e.g. `12000`) - `{{OUT_BIN}}` (absolute path) - `{{FB_ADDR}}` (e.g. `0xD0000000`) - `{{FB_SIZE}}` (e.g. `0x1C5000`) ### 2) Dump raw framebuffer ```bash JLinkExe -NoGui 1 -CommandFile /tmp/jlink_dump_fb.jlink > /tmp/jlink_dump_fb.log 2>&1 ``` ### 3) Convert raw to PNG ```bash python3 scripts/dump_fb.py \ --in /path/to/fb_dump.bin \ --out /path/to/fb_dump_604x1024.png \ --width 604 --height 1024 --stride 3 ``` ## Troubleshooting - If output bin is 0 bytes: check J-Link connection / path permissions. - If colors look wrong: verify pixel format is RGB888 (not BGR / RGB565). - If image shifted/corrupt: verify width/height match current display mode. - If command hangs too long: make sure dump size is correct (`0x1C5000` for 604x1024 RGB888). ## Notes - This method captures **real framebuffer pixels** (no camera distortion). - Best for Figma-vs-device pixel comparison and regression snapshots.