Lpc2000

Hi there,

I just finished a project with the same problem. For the third UART I've used a SW made uart via GPIOs and it works @ 115200 baud rate. 

As for the OS I used mine, uSmartX. The OS can inform you when there is nothing to do (scheduler reurns SYS_IDLE) and I'm idling the CPU at that point. My power consumption dropped for ~30%.

If you want visit http://usmartx.sourceforge.net/ for more information regarding the OS.

Hope it helps,
marko

> 
> Od: "guillermoprandi" <yahoo.messenger@...>
> Datum: 2005/10/06 \ufffdet PM 02:37:46 CEST
> Za: lpc2000@yahoogroups.com
> Zadeva: [lpc2000] Low power multithreaded OS suggestion?
> 
> Hi! I am building a board featuring the LPC2138 ?C. This board will 
> basically need to interface with three serial devices (two via 
> internal UARTs and a third via MAX3100, though suggestions are 
> welcomed about this). This device must be very low power; it should 
> wake up only when needed, which is: 1) there's data available from 
> any of the three ports, 2) there's data waiting to be transmitted on 
> any of the ports and the port becomes free and 3) a periodical 
> overall check (every second or so). This means that theoretically the 
> processor can enter the idle state quite often. I'm looking for some 
> (free if possible) multithreaded OS that would handle the transition 
> to the processor's idle state on traditionally blocking calls like 
> fread() and fwrite(), expecting to wake up on interrupt; also, some 
> preemptive multitasking should be supported, in case some thread 
> enters an exceptionally long calculating task. Probably there's no 
> known OS that directly supports this; in this case, I'd like to know 
> which other OS might be a good starting point to accomplish this by 
> making the modifications myself. I'm aiming to use the GNU libraries 
> (I ignore how difficult or messy would it be to modify them to 
> support this). Finally, it is my understanding that the VERY low 
> power "power down" mode would not be useful for my application, since 
> the peripherals (therefore the UARTs and SPI) are shut down in this 
> mode. Any advise or hint on these subjects will be greately 
> appreciated.
> 
> Guille
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