Embedded Internet enabling methods: Which?
TOM THERON email (remove spam text)
----- Original Message -----
From: William Chops Westfield
Sent: Tuesday, May 30, 2000 9:03 AM
Subject: Re: [EE] Embedded Internet enabling methods: Which?
IMO (not very humble - I've got a fair amount of experience in this area),
this isn't possible. To start with, the protocols pretty much assume an
environment with "separate" operating system and applications, which will
get you to pretty large code (for the "OS" side, which has to have
"everything") pretty quick. Implementing Internet connectivity on a small
microcontroller means cheating. How badly you cheat, and where, and whether
you'll be able to get away with it on a large scale, is dependent on how
much space you're willing to sacrifice to the network code (and it IS
primarilly a space issue, rather than a speed issue.)
Possible approaches with "minimal" cheating:
1) Code-generator type scheme, where your code is carefully analyzed,
and a "custom Network OS" is generated that implements ONLY those parts
of the stack that you actually use.
2) an interpretter (basic-stamp-like, I guess) with a very large external
memory... (here, performance might start to be an issue, of course. An
interpretted OS with applications written in assembly. Weird.)
As a reference or starting point, you might consider NCSA telnet, an "open
source" (but predating that term) application/OS/Internet stack that runs on
DOS. a 1990 ("pre-bloat but post-64k-frugal") implementation has a
"minitel.exe" program without too much extra stuff (like tektronix terminal
emulators) and is about 93kbytes (for the exe file.) Other possibilities
include "ka9q" - a similar project targetted (restricted?) to ham radio
I am primarily looking at a 8051 based system, thus DOS would not serve the
purpose, although if nothing else I can possibly move to an 80188 platform.
But it might be something to look at as part of the learning curve.
See also: www.piclist.com/techref/index.htm?key=which
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