16/32 bit processor for OS development

Can anyone recommend a 16/32 bit processor for someone who doesn't have much money. I would like to play around with a higher end processor (I'm dinking around with 8bitters like AVRs, PICs). I also would like to make an embeddd OS in C for the processor.

So can anyone recommend a processor with cheap development boards?

Reply to
Lax
Loading thread data ...

If you ask the right people you'll get a development board for an obsolete Pentium for next to nothing. You can expect it to have a hard drive (small), keyboard port, video port, and other handy ports. You can even expect to have it come with a power supply and be in a nice looking case!

They're called "old PCs".

--
Tim Wescott
Control systems and communications consulting
 Click to see the full signature
Reply to
Tim Wescott

I meant an Embedded processor on a development board aimed at Real Time applications.

Reply to
Lax

Go to the junk yard and get an old PC.

You can enjoy all of that. There is plenty of documentation and software, too.

Intel P-II or Celeron, probably. The earlier boards are already vanished, the newer boards are still in use.

VLV

Reply to
Vladimir Vassilevsky

ARMs ? - tho they've probably been done to death. Perhaps AVR32 ? Or the Zilog Z16F ?

- for the Zilog Z16F, you can download the tool set for free, and it includes a CPU simulation mode, so you can test to a first pass, without needing any development boards at all! Tools support a good mix of ASM and C.

Not sure if the AVR32 Studio has Simulation yet ?

-jg

Reply to
Jim Granville

Why would you want to create yet another OS for the board you end up selecting when there are already plenty of them around and given the fact that most embedded real time apps don't use an OS at all.

You say you have been dinking around with AVRs and PICs for a while so what sort of applications are you doing with those? Would the 16/32 bit versions not be similar projects?

BTW I can understand if it is for an element of self education. You mentioned high end 16/32 bit processors as a requirement. A clue about what you are trying to do and the performance requirements would have been helpful. I guess ARM might be considered one way to go but there are also some PC104 based processors that are virtually mini-PC's and if you hunt around there may now be a few available second hand. In fact I might still have one going begging for a good home (486 based). I would have to look in the storage boxes.

--
********************************************************************
Paul E. Bennett..................
 Click to see the full signature
Reply to
Paul E. Bennett

So did Tim.

--
 Chuck F (cbfalconer at maineline dot net)
   Available for consulting/temporary embedded and systems.
Reply to
CBFalconer

Upon what evidence do you base that assertion? Certainly there are plenty of real-time apps that are running in task loops, but if you include a real-time kernel in your definition of "OS" then there are plenty of real-time apps that are running under RTOS's.

I suspect that if you count by shipped units there are more microprocessors (not microprocessor types) running without RTOS's, but if you count by developer there's more people working with them.

Either way, I don't know the answer for sure and would be interested if you have something concrete that you could point me to.

--
Tim Wescott
Wescott Design Services
 Click to see the full signature
Reply to
Tim Wescott

I was, indeed, thinking of the measure by shipped units (from simple toys through to some quite complex machine control systems).

Are any of the measures really concrete? My statement was based on a strong gut feel from having read a number of articles in several embedded systems magazines (mostly the state of play types).

--
********************************************************************
Paul E. Bennett...............
 Click to see the full signature
Reply to
Paul E. Bennett

Sorry for my ignorance.

Say I get an old PC. How would I wipe off all the firmware (BIOS) etc. and then reburn my own stuff on it? I would like to manipulate the processor fully on my own like I do with PICs.

How would I convert it into my own personal embedded development platform? Right now with PICs, AVRs, I cross compile and then burn it into the chip using a programmer (usually can be all done on the development board like STK500).

But with an old PC, I don't even know how the processor, BIOS, etc. is wired up specifically on the inside. I guess the first step is to learn how it's all wired up? Next step would be to wipe all the firmware off. Then final step would be to figure out how to replace the Flash Bios chip with my own chip that I can burn externally?

This is for self education purposes like another poster guessed. I haven't been lucky enough to get an opportunity to do OJT for this kind of work, so I have to improve my resume the hard/expensive/time- wasting way with some hobby experience with some 16/32 bitters on top of the 8 bitters (thank god for Microchip's cheap stuff!).

Reply to
Lax

All you need to find out is how the first bootstrap works (it loads a single sector into a fixed location, and transfers control). You can make that do absolutely anything you want - no need to wipe anything out. It is dependent on the bios, but what it loads need no longer depend on anything. Have fun.

--
 Chuck F (cbfalconer at maineline dot net)
   Available for consulting/temporary embedded and systems.
Reply to
CBFalconer

As part of the boot process the BIOS hands the program counter over to the boot code from disk; at that point you can ignore the BIOS if you want to.

Were I going to do this I'd get a copy of RTAI Linux, or that other real-time Linux, and build applications on top of that. You won't be all the way down to bare metal for anything but custom hardware that you add or possibly printer ports, but for 32-bit development you often aren't that deep anyway.

Later, if you want to play with the BIOS then you could, but only if you really needed to do something unique with the hardware, since you can always just bypass the BIOS.

--
Tim Wescott
Wescott Design Services
 Click to see the full signature
Reply to
Tim Wescott

There is a ROM scan procedure; one can install the additional ROMs of his own.

Linux for linuxopaths. Windows CE rulez.

Why not? One of the problems of the development for the PC is that most of the tools assume some environment; not the bare metal. It is not very trivial to make an executable image with the physical addresses in it.

The native BIOS initializes the board and the chipset. For that reason I wouldn't mess with it.

Vladimir Vassilevsky DSP and Mixed Signal Consultant

formatting link

Reply to
Vladimir Vassilevsky

Do you count units shipped by Mattel and Hasbro as being real-time embedded systems? Digital wristwatches? PC keyboards? Dishwashers? calculators? Programmable thermostats?

For every PIC, 8051, or ARM uC sold I estimate at least a thousand Elan/EMC, WinBond, or SunPlus uCs sold. The number of engineers and projects are far smaller, though; how often do you need a part with masked ROM, a minimum order qty of 50K or 100K, and cost under a dime per uC including all external components?

The profit for the manufacturer on these is well under a penny per uC, so that 50,000 unit minimum order will cost you $5000 and the manufacturer will make less than $500 on the deal. One of my projects at Mattel ended up in production at a rate of

100K units per hour, so low cost was quite important.
--
Guy Macon
Reply to
Guy Macon

Use the BIOS and DOS to load your program into memory, then let your code have 100% full control of everything with no calls to the BIOS.

It shouldn't matter to you whether your code is executing from an EPROM you burned or RAM that you loaded from disk, as long as that code takes over the machine.

As for the hardware details, they aren't all that hard. You can, for example, ignore the video, keyboard, etc. and do everything through bitbanging the parallel port.

--
Guy Macon
Reply to
Guy Macon

You guys seem to be on a whole another level. Using an old PC is going to require a lot of hacking on my part, and I totally lack the knowledge of IBM PC boot sequence, hardware, etc.

Can anyone recommend some good website (or even books) that can help me TAKE CONTROL of the old PC like everyone is suggesting? Wouldn't this hack be specific to the type of PC I am using?

So far my searching is not giving me good results. For example websites like

formatting link
don't have much details (not enough details for a hack).

Reply to
Lax

As was already described to you, the PC boot sequence is quite straightforward and completely documented. You have some choices to make: Do you want your system to run from a floppy, a hard drive, or from EPROM? The BIOS will automatically scan for "BIOS extensions" in a fixed address range. Your code, or a jump to your code, can reside there. OR: The BIOS will read the boot sector of a floppy disk, and jump to the address specified at a particular offset. OR: The BIOS will read the partition table of a hard drive, locate the partition marked as bootable, read THAT boot sector, and jump to that specified address.

Find an old copy of Peter Norton's "Inside the IBM PC" to learn exactly how these are accomplished. The older editions are about $1.00 used.

--Gene

Reply to
Gene S. Berkowitz

It's not as weird/hard as you think it is.

Consider: the PC's been around now since early '84, IIRC. Back then, it was a micro with a human interface, which was well defined and set in stone. What we use nowadays is just a rather faster version of the same thing, but LOUDER.

Steve

formatting link

Reply to
Steve at fivetrees

after avr and pic, arm7 would be good choice. (LPC and SAM7 parts are very good documented, ST M have cortex m3 processors which are "new & improved" :)

formatting link
formatting link

yusuf

Reply to
tesla

In article , Lax writes

ARM7

Lots of inexpensive boards about and most can be programed by the serial port if you can't afford a JTAG.

Also there are several FREE OS (freeRTOS, Mu/COS etc) that will run on it you can use for inspiration for doing your own OS

Do not use an old PC.... it is not used in the embedded world and is far too complex for a start point. More to the point it has a Bios in there and needs complex drivers.

--
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
\/\/\/\/\ Chris Hills  Staffs  England     /\/\/\/\/
 Click to see the full signature
Reply to
Chris Hills

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.