On 2009-04-04, DEAU wrote:
Does anyone know where I can find some of the interface adapter chips used
in those USB-to-SD card adpaters? This looks like it transparently converts
USB data into SD (or possibly SPI) protocol to write/read to/from the SD
card.

Does anyone know more about these chips?

they convert SD (either serial or parallel) to "usb-storage"
they can probably not be used as generic SPI interfaces.