Fullsize SDCard?

Besides @Bradley_Bratten taking the initiative to hack something up, are there plans to create a full-size SDCard expansion slot?

Us with digital cameras, that’s all we have - and I hate carrying dongles around (current laptop is a dying breed, supporting full-size sdcard which is the single only reason I bought it as I don’t like the brand).


It’s an absolute crap show the only way I know for it to at least interface is using USB to UART and then UART to SD but that requires terminal to use.

@Josh_Cook SPI mode is not acceptable for any photographers or videographers. It’s extremally slow comparing to the native SD mode or SDIO for SD/SDXC/SDHC or the newest NVME PCIe-compatible protocol for SD Express standard.

On it – there is an excellent USB3.0 → SDIO interface microcontroller available from NHK electronics ( Shenzhen ) that will do the trick. It’s a really tiny part ( mBGA!!! ) and low power The tricky thing will be to get the mechanical design tight enough to fit into the shell size for the expansion bay.

This will ONLY work for SD, high capacity SD, but won’t work with specialized SDIO cards like wireless expanders, or ones that export UART … but if you’re a photographer or someone that needs to dump full sized SD cards it should work.

If interested – please <3 this comment. That will help me determine potential demand for the expansion card and if it’s worth my time to develop and debug it.


It will be extremely slow, already have mentioned using UART and it’s 115,200 baud or 0.0144 MB a second standard. You would have to have over a billion baud which is impossible. And it won’t work with high capacity so for photographers or videographers so won’t be fun.

The existence of high-speed USB SD readers that aren’t limited to 115kbaud seems to trivially disprove this assertion. Why would such a device be limited to UART if you just changed its form factor?

I was wrong, I thought you said SPI, anyways SDIO is 300kilobytes a second with 4 bit.

@Josh_Cook : Your assertion is incorrect.

There are now USB3.0 to SD/SDIO bridge chips. That’s why I was talking about integrating the NHK chip to do the job. It provides a native high speed SD->USB3.0 bridge.

It’s similar to the prolific PL2733 USB 3.0 bridge ( which includes things we don’t need light Lightning compatibility ) which you might already be familiar with: Products

It’s the same chip ( with hard to find documentation ) that is used in products like this one, with support to up to 5 gigabit transfer speeds, as well as full support for SD, SDHC, and SDXC.

Now, the only downside is that I don’t think I will be able to fit BOTH a microSD and full size SD card together into the slot. I was looking on LCSC and other markets for a 2-in-1 adapter that is thin enough, or an SMT mounted one that would fit within the dimensions of a 1mm board top/bottom mounted… but I can’t -quite- make them both mechanically fit. Since Framework already offers a miniSD adapter, that may not be too big of an issue… since if someone REALLY needs a dedicated port vs carrying a USB-C->SD adapter… they probably have chosen one over the other.


Why can’t you just use a full SD microSD adapter when needed? Those adapters are very common and can just sit in your SD slot until you need the full SD.


Are you talking about something like this? Saiko Systems Ltd. - SD to MicroSD Converter

My first thought was “it looks like it would snap off or harm the microsd reader”… but I suppose you could replace if it breaks (or breaks something).

I have a 3D printer that uses full size SD card and I want to quickly ship data between the laptop & 3d printer. I guess I’m just interested in convenience.

I believe @TimeMage meant an adapter to make the microSD fit an SD slot, like the ones that often come with microSD cards. That way if you have a SD reader in the machine, you just leave the adapter in the slot for microSD use, and pull it out when you need to use a full size SD.

I’ve gone back and forth on this issue myself. For now, at least, I’m pretty happy with this little USB-C adapter for when I need it:


That said, if my use case had me doing memory card work routinely, having it in an expansion card would be very handy. And if a dual slot expansion card isn’t possible, the above solution seems like a reasonable alternative.

I made a very DIY full size SD card Expansion Card that you can check out below.