The interrupt structure within the ARM7 CPU and the VIC dose not support nested interrupts . If your application requires interrupts to be able to interrupt ISRS then you must provide support for this in software. Fortunately this is easy to do with a couple of macros. 上面是老外书上抄下来的。按我的理解,如果要在ARM7实现中断嵌套,必须加入额外的宏或者代码。而我用PIC24的时候,只需要设置好中断优先级别,高中断自然可以打断低中断,由于在ISR的出入口是用POP和PUSH(编译器产生)指令进行保护和还原,我不需要太关心。这就是我所谓的"天然".