> I have access to some 486 (and 386) single board computers that I'd
> like to utilize for some one-off projects. While I've programmed PCs
> under DOS (Windows too, but I have no need for Windows on these
> boards), I've never programmed an x86 SBC. I have, BTW, programmed
One tends to design in x86 only when running a COTS OS is part of the
design requirements. Otherwise it's not a very efficient solution.
I'd recommend looking at various realtime Linux flavors on the 486s.
Reply by CBFalconer●July 13, 20052005-07-13
Mike Silva wrote:
>
... snip ...
>
> To summarize, I want to program some 486 SBCs, and I have some
> bias towards 32-bit code but it's not a must, and I want to do it
> cheaply and easily, and will probably want an RTOS at some point.
> Not too much to ask, eh? :-)
Check out DJGPP, at www.delorie.com. No need to restrict yourself
to 16 bit code.
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Reply by Richard●July 13, 20052005-07-13
> I gather that I could stick a DOS on these and program them using a
> 16-bit compiler. I do have MSVC++ 1.52c which includes a 16-bit
> compiler. What other options would I have for 16-bit programming?
>
> What about 32-bit code (the idea of having to think about nears and
> fars again gives me pause)? What's involved in writing 32-bit code for
> a 486 SBC?
Using DOS extenders can be a headache, having both real and protected mode
ISR's. If you want 32bit protected mode and have a few $ to spare, then
http://www.on-time.com provide a very nice system. You say you want to do
it cheaply, but this is a relative term. The on-time tools are relatively
cheap compared to others, but still you must part with some cash.
> Oh, and I'll probably want to use an RTOS for one or two of these
> projects. Would I be able to e.g. launch an RTOS from DOS?
The on-time product allows you to do exactly this. Very nice.
>What about
> running an RTOS in 32-bit mode? I'd incline to something free like
> uC/OS-II or FreeRTOS or eCos (none of which I've used before, but I've
> used a number of others that the bosses paid for). Any thoughts there?
FreeRTOS.org is 16bit only (unless you want to provide a port :-) ), x86
is not a primary target other than the low end 1/286. Not sure about
uC/OS-II, but this is only free if you are not intending on creating a
commercial product.
Regards,
Richard.
http://www.FreeRTOS.org
Reply by Mike Silva●July 13, 20052005-07-13
I have access to some 486 (and 386) single board computers that I'd
like to utilize for some one-off projects. While I've programmed PCs
under DOS (Windows too, but I have no need for Windows on these
boards), I've never programmed an x86 SBC. I have, BTW, programmed
plenty of embedded stuff using other processors. Can any of you folks
who have done so tell me something about my options in the 32-bit x86
embedded world?
I gather that I could stick a DOS on these and program them using a
16-bit compiler. I do have MSVC++ 1.52c which includes a 16-bit
compiler. What other options would I have for 16-bit programming?
What about 32-bit code (the idea of having to think about nears and
fars again gives me pause)? What's involved in writing 32-bit code for
a 486 SBC?
Oh, and I'll probably want to use an RTOS for one or two of these
projects. Would I be able to e.g. launch an RTOS from DOS? What about
running an RTOS in 32-bit mode? I'd incline to something free like
uC/OS-II or FreeRTOS or eCos (none of which I've used before, but I've
used a number of others that the bosses paid for). Any thoughts there?
To summarize, I want to program some 486 SBCs, and I have some bias
towards 32-bit code but it's not a must, and I want to do it cheaply
and easily, and will probably want an RTOS at some point. Not too much
to ask, eh? :-)