The microSD card: files, photos & video

The microSD card part is a real 64 MB card, pre-formatted the way store-bought cards come (FAT16). Firmware mounts it and reads files from it exactly as it would on a physical bench — the "microSD photo frame" example is a complete working project: an ESP32-C6 reads pictures off the card and shows them on a little TFT screen.

Putting your own things on the card

1. 1Click the card on the bench, then Add to card… in the panel on the right.
2. 2Pick any file. Pictures and video clips are prepared for the tiny screen automatically; anything else is stored exactly as-is.
3. 3The board restarts with the new card contents — with the photo frame example running, your picture joins the slideshow and a video clip plays at its own speed.

Why "prepared"? A microcontroller is a tiny computer — it can no more decode a JPEG or an MP4 than a real Arduino can. Real projects solve this by converting media on a PC first, and Breadboard does the same, just automatically: pictures become raw screen-ready pixels, and clips (MP4, WebM, or an animated GIF) become a stream of frames the firmware plays by copying bytes to the screen. The preview in the panel shows exactly what the card will hold — small and a little chunky, because the screen is 160×128 pixels. That's the honest look of the real thing.

The card's rules of thumb

• Names get shortened. Old-school SD cards use 8-character names in capitals ("8.3" names) — holiday-clip.mp4 becomes HOLIDAY_.565. The firmware sees the short name.
• Up to 16 files, and a clip tops out around 4 MB — roughly 25 seconds at 10 frames per second. The converter tells you if it had to cut a clip short.
• Editing the card restarts the board, the same as pulling and re-inserting a real card.
• What you add here is part of the circuit: it saves, shares, and syncs with the document. Files the firmware writes at runtime (data logging, for instance) are not kept after a page reload — the card starts fresh from the document each time.

For the firmware-curious

Open the Code tab on the photo frame example and you are looking at the whole thing: a ~40-line SD driver (the same one every real SPI-mode SD project starts from), a FAT mount, and a loop that copies bytes from the card to the screen. Pictures are .565 files (a tiny header, then raw pixels); clips are the same with a frame count and a frame rate in the header. The full format spec, pin wiring, and sharp edges live in the Component reference under microSD.