Hi! This dsPIC code sequence: MOV.B #0xE0,W0 MOV.B WREG,SR does NOT disable the IRQ's. I'm quite desperate.. why's that? I tried to write 0xFFFF to the register, and what I read back is 0x010F, i.e. the IPL bits seem not writable! Even setting bit IPL3 in CORCON doesn't prevent interrupts from occuring. Sure, I can disable the sources, but since I've worked up the prioprities for them carefully, the best way would be the one that seems by design for the dsPIC, i.e. to set a minimum interruptable level in SR! But it doesn't work! Thanks, Mario -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist