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DS development > arm9/arm7 communication

#140691 - ingramb - Wed Sep 19, 2007 4:12 am

I am trying to set up code on the arm7, and I need my own IPC region. So I set up something like this:

//occupy ram past the end of devkitpro IPC @ 0x027FF000
#define NEOIPC ((volatile TNeoIPC*)(0x027FF800))

Whenever code on the arm7 side touches this struct, it seems to freeze the system. Both the arm9 and the arm7 stop working. All tests are done on a real nds.

The arm9 can access it just fine. The arm7 can access the standard devkitpro IPC just fine. Is there something I'm missing?

[edit]
Just thought I'd add that TNeoIPC is 12 bytes, so I don't think I'm overflowing memory.

#140692 - ingramb - Wed Sep 19, 2007 4:32 am

Seems I solved my own problem. I just have to wait a while on the arm7 side before touching NEOIPC.

I'm still curious as to why I need to wait though.