Re: [ECOS] Prototyping with the synthetic target.

[Andrew Lunn <andrew dot lunn at ascom dot ch>]

On Mon, Jul 29, 2002 at 12:31:43PM -0700, Chuck McParland wrote:
> Prototyping with the synthetic target.
> 
> I'd like to do some application prototyping and simulation
> work using the synthetic target and would appreciate
> any pointers from those who have gone through this
> before.
> 
> First task is to be able to pass messages between an
> ecos application running inside the synthetic target and
> a second linux process on the same machine.  Local
> sockets would be ideal; but it's not clear whether the
> network stack works on the synthetic target. 

The network stack works as a network stack without any device drivers
(except loopback). There is no connection to the host OS's network
stack, so you cannot use it for IPC between eCos and host OS
processes. You can use it for IPC between eCos threads.

> Named
> pipes are also a possibility. Has anyone used them?

Yes. You have access to the Host OSs system calls using the hal_sys
backdoor. We have used both the TCP/IP stack, Unix sockets, and fifos,
using the back door. If you look back in the archive for ecos-discuss,
you can see the answers i've given to other people who have asked this
question.

> Secondly, could anyone point me towards further
> info on the synthetic target?  I've been looking through
> the hal/synth tree and can't quite work out the relationship
> between the ecos system calls and the linux calls.

There is none really. The synth hal just uses a few limited host
system calls to implement a timer interrupt and the HAL diagnostic
tty. Things like eCos fileio uses eCos's fileio code. You can add
eCos's RAM FS to access eCos RAM filesystems. You can also do the same
with ROM FSs. There is no access to the host file system using
fileio. If you want to manipulate host files you need to use the
backdoor to the system calls.

My experiance of using the synth target for application prototyping is
good. It needs some extra effort, simulating your target hardware, but
i find the debug environment much faster to use than real hardware. 

  Andrew

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