Comment by duskwuff
4 days ago
You're correct on both points.
Some early wireless cards used SDIO to communicate with the host computer. These are long gone.
There were also some later SD cards which contained an embedded controller running Linux, which emulated an SD storage card and exposed its contents over wireless. The latter are what that article was about.
I'm currently using an Ezurio WiFi/Bluetooth module in a project and it still uses SDIO to communicate with the host. Only difference is that it's a much smaller module welded down to the PCB.
The dev kit, however, still has the traditional interface.
https://www.digikey.com/en/products/detail/ezurio/453-00045-...