Usage of Expansion RAM

[sahack]

(New to DS programming, complete noob here. First post)

I was think that there happen to be the official slot-2 ram expansion kit from Opera for DS, and there are 3rd pty tools like EZ 3in1 that provides 16MB extra RAM.

I don't think I've found info from the devkitARM sdk or the libnds headers. I've also checked information on EZ-Flash's siite, no sdk for their product either.

So, could anyone give me advice on using the slot-2 ram expansion? If it's not available to use, tell me as well. Thanks in advance.

[Dwedit]

Expansion RAM is the slowest RAM available, since there are so many waitstates to get to the cartridge slot. You can only write there in units of 16-bits or higher, 8-bits writes will copy the byte to both parts of the halfword, just like VRAM on the GBA.
But the speed problems are highly reduced when you enable caching for expansion RAM.

You should try to support all known GBA-slot cartridges which have RAM in there. There's a library to unlock the RAM on the M3, G6, Supercard, etc, so you don't have to do anything special yourself except call the unlock code, which attempts to unlock every type of cartridge.
Link: Lick's RAM unlocking API: http://forum.gbadev.org/viewtopic.php?t=13023 note: links to files are broken, Mirror here

[sahack]

Expansion RAM is the slowest RAM available, since there are so many waitstates to get to the cartridge slot. You can only write there in units of 16-bits or higher, 8-bits writes will copy the byte to both parts of the halfword, just like VRAM on the GBA.
But the speed problems are highly reduced when you enable caching for expansion RAM.

You should try to support all known GBA-slot cartridges which have RAM in there. There's a library to unlock the RAM on the M3, G6, Supercard, etc, so you don't have to do anything special yourself except call the unlock code, which attempts to unlock every type of cartridge.
Link: Lick's RAM unlocking API: http://forum.gbadev.org/viewtopic.php?t=13023 note: links to files are broken, Mirror here

Thanks a lot for the info.