Re: [ECOS] memory requirements, TI OMAP 5910 (ARM 925T)?

["Gary D. Thomas" <gary dot thomas at mind dot be>]

On Fri, 2003-07-18 at 15:43, Jim Partan wrote:
> Hi,
> 
> I'm starting to evaluate the TI OMAP 5910 (ARM 925T) for a new embedded 
> system. I'd like to use eCos. Right now I'm specifically trying to 
> estimate the approximate memory requirements. I'm just getting the eCos
> configuration tool up and going, but if anyone has a vaguely similar
> system and can let me know what their approximate memory usage is, that 
> would be great!!
> 
> I'm interested in using (on ARM 925T):
> 
> 	TCP/IP stack with embedded webserver
> 	ethernet driver (perhaps SMSC LAN91c111)
> 	flash filesystem
> 	RS232 serial port ('5910 has some integrated UARTs)
> 	an external realtime clock (probably on I2C bus)
> 	maybe a few other very small things (watchdog, etc)
> 
> 	ideally USB as well, but this is not at all critical
> 		(the '5910 has an integrated USB interface)
> 
> The OMAP 5910 has 192kbytes of internal SRAM. I'd love to avoid
> putting an external RAM chip on the board. The catch is that
> the internal SRAM is shared with a TI DSP sharing the same
> package (it's a dual-core package, ARM 925T and TI '55x DSP),
> and of course I'd like as much RAM as possible dedicated to the
> DSP side of things...
> 

Not counting any particular other application support (like
the web content generation, etc), a rough guess is that you're
talking 300-400KB of code, which might possibly run from FLASH.  
Having only 192KB RAM might be doable, but I think you'd suffer 
network performance.  By default, the network stack uses 256KB 
for it's own data (buffers, structures, etc), but of course 
this is configurable.  In this case, you'd be trading memory for
performance.  It does look like external RAM would be useful
(probably even required) for you to make much of a useful system.

-- 
Gary D. Thomas <gary.thomas@mind.be>


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