[Tinyos-help] Some confusion on the classic nesC paper.

[David Gay]

On 7/9/07, Zhifeng Lai <zflai at ust.hk> wrote:
> Dear David,
>
> I do not have the background on developing embedded systems; I started to
> learn nesC half a year ago for research purpose.
>
> Do you mean that some commands in avr library that manipulate memory-mapped
> I/O will enable interrupts as a side effect? If so, could you give me some
> concrete examples (I just learned that the "sei" macro in avr library can
> enable interrupts)?

  *(int *)0x5f |= 0x80;

does the same thing as "sei" - the SREG register is memory-mapped to
address 0x5f. Read the Atmega128 datasheet for more information.

And read up on memory-mapped I/O and DMA if my previous comment didn't
make sense.

As to whether application programmers would do this, you'd have to ask
them. But it sounded like you wanted to *prevent* this, not just
assume programmers didn't do it...

David Gay