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I’m open sourcing TinySD, a dependency-free C library for SD cards and SDIO on embedded and bare-metal systems - github.com/loopj/tinysd

James Smith

@loopj.com

TinySD supports SD memory cards (SDSC, SDHC and SDXC) and SDIO devices, both with high speed support. No dynamic allocation, and no threads, callbacks or interrupts required.

James Smith

@loopj.com

I built this after writing "just enough SD" for three separate bare-metal projects, and deciding it was time to do it properly. Everything else either forced a filesystem on me or was framework-specific.

James Smith

@loopj.com

It ships with an SDHCI host driver for SD Host Controller versions 1 to 3, plus a simple interface for adding your own hosts. If you’re bit-banging the bus or driving it with PIO, CRC and framing helpers are included too.

25/10/26, 3:55 am0 reposts1 like

James Smith

@loopj.com

TinySD just reads and writes raw blocks, so you can bring your own filesystem. It pairs nicely with ChaN's FatFs, littlefs, etc.

James Smith

@loopj.com

I’m releasing it under a permissive license (MIT), in the hope it can be a useful building block for other embedded projects. Excited to see it out in the wild!