What tools and approaches for programming 486 boards?

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? :-)

Reply to
Mike Silva
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Take a look at

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and
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if you would like a 16bit environment, with perhaps a DOS extender.

Alternatively try

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for a 32bit under DOS.

Both these tools are open source.

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

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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.

The on-time product allows you to do exactly this. Very nice.

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.

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Reply to
Richard

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Check out DJGPP, at

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No need to restrict yourself to 16 bit code.

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Reply to
CBFalconer

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 to
larwe

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