Lpc2000

>Thanks, Gilles. Do you mean that free RTOS already handles entering
>the processor's idle mode off-the-box? Or should I mod it in order to
>achieve that? Does the 2106 port applies to 2138 without needing any
>modifications?


The idle task will automatically execute when there are no user tasks able
to do so.  If you want low power, then the idle task can place the processor
into a sleep mode - this way the processor will automatically power save
whenever there is no processing to do.

The idle task is then nothing more than:

for( ;; )
{
    sleep_now(); // user defined.
}


Pre-emptive schedulers such as FreeRTOS configure a timer to generate a
periodic 'tick' interrupt.  Each tick interrupt will wake the processor, so
the faster the tick frequency the more power the processor will use.

The demo serial port drivers included in the FreeRTOS download use queues to
pass serial port data from interrupt routines to user tasks.  The interrupt
is fast as all it does is read the character from the register and place it
into the queue.  The task that processes the data can block on the queue
waiting for data to become available, so does not use any more processing
power than necessary.

Regards,
Richard.


http://www.FreeRTOS.org