This archive contains all the files that you need to program a DSerial (EDGE). The mcu folder contains the firmware of the onboard MCU and the nds folder contains a sample code that lets you upload the current firmware to the card. You can copy the card_spi files, the dserial files and the mcu file from the source folder to use the DSerial in your own projects.
The files work with the latest libnds version according to my tests (but I didn't test everything).
Change log (1.3.2):
Updated code for libnds (1.4.5) shipping with devkitARM r30