Dev. board options

[johnames]

I've got a coding project in the works targetting m68k/Coldfire and I'd like the option to run on real hardware rather than just in a simulator, but I'm having a devil of a time tracking down anything that would be suitable for my purposes. As far as I can see, it seems like the only such products that are still generally available on electronics supply sites like Digikey and Newark are in the neighborhood of $100-200 for something that includes less than a megabyte of flash memory and 8-32KB of RAM, and more often than not is just a bare board designed for Freescale's "tower" system. (Considering they used to make Coldfire development kits that would run an embedded Linux, that's a pretty appalling state of affairs.) I've seen specs for older boards like the MCF5208 or MCF5485 that look more like what I'd want, but they seem to be pretty much completely unavailable.

What I'm looking for is a development board or other standalone SBC that has one or two serial ports, at least 128KB of RAM, and ideally a megabyte or two of flash storage. (I'm not looking to use a vintage 68k computer system like a Mac or Amiga, since using those involves not just using the processor, but learning my way around all the quirks of the system hardware and circumventing the normal boot process.) I'd be happy with more, but that's what I'd consider necessary for my goals. I'm open to building something myself, if the parts and board are fairly easy to procure. Is there anything like that out there currently, or readily available second-hand?

[yibbidy]

Just throwing it out there, but if you can get by with half a meg of flash, and a "real" 68K takes your fancy you might like to look at:

RoboMinds

For USD89 you'll get a MC68332 with 512kB flash, 512kB battery backed RAM.  Another USD40 will get an old school BDM cable (plugs into a parallel port).  I've got one of these somewhere that I used ten or so years ago that worked very well.

The Netburner core modules that Tom suggested are excellent also, I've got a couple of those.

Good luck, Shaun

[TomE]

This question was also posted on comp.sys.m68k.

A very good answer has been posted there:

https://groups.google.com/d/msg/comp.sys.m68k/h7zjB6rOfmo/6bW52RjXBgAJ

> If you're still searching, take a look at <www.netburner.com>.

That site lists the following "core modules":

MOD5213, MOD5234, MOD5270, MOD5272, MOD5282, MOD54415, NANO54415

Tom

[TomE]

Why START on a ColdFire development? All the action has been with the ARM (Kinetis and i.MX) ones for quite a while now.

If you have to, make sure you pick a chip that has some life left in the "Product Longevity" program, like the MCF5329 that I used recently. It has "Development Boards", that are listed on NXP's site as "no longer manufactured". And the chip is "not recommended for new designs".

In fact on the "Product Longevity" list there are only a couple of "MCF51" small and simple MCF chips, and one MCF5441x which was launched in 2010 with a 15 year life (except the Parametrics page only says 10 years). But they're the only "current chips" in the family. The MXF5441x looks to be only supported by the Tower.

The longevity of the other chips in in the "archived longevity list".

Tom

[johnames]

I'm well aware that it's not the Official New Direction. But I vastly prefer the m68k/CF architecture to the full-RISC architectures, and since it's a personal project and not a commercial one, I'm not really bothered by things being EOLed, except in that it seems to make it difficult to get ahold of good base systems.

[TomE]

Excellent! What you want depends on whether it is "development" with final production on something else, or if you intend to "field the development system", in which case a single board would be better then the "box of sockets" that is a Tower system, and buying enough bits. If it is only there for the joy of getting software working on it then it doesn't matter.

Get enough readers and someone might sell or give you an unused development system from their "random old hardware cupboard".

> less than a megabyte of flash memory and 8-32KB of RAM

That was a LOT when these things were new!

But just in case it suits, eBay finds:

Freescale Semiconductor Tower Module MCF5225X Coldfire With MQX Rtos | eBay

I also helped someone on this list a while back reverse-engineering a system based on the "Cobra5272", which there are still web pages for:

COBRA5272 - ColdFire Board for Rapid Applications mit MCF5272

It looks look it would be ideal with "Zwei serielle Schnittstellen (SCI) mit RS-232 Treiberschaltung" and "2 MByte Flash und 16 MByte RAM auf dem Board". Except Google Translate tells me "nicht mehr im Sortiment" means "no longer in assortment". Also, archive.org tells me went obsolete in early 2013, and it was 500 Euros THEN.

COBRA5272 - ColdFire Board for Rapid Applications mit MCF5272

Still, it might be worth emailing them in case they have an old repaired or demo unit there somewhere.

There are a lot of projects out there based on some popular Netgear router/modem boards. Maybe some of the older ones had Coldfire chips in them.

If you can find one of these buried deep in the back of a cupboard (or basement or attic) at a University somewhere, I might be able to help. 16MHz 68331, as much Flash as you can plug in (about 1M max) and four 1993-dated 256k or 1M RAM SIMs (so 4MB Max). With Parity even, that's how old the design is!

MultiPort/LT Features

> at least 128KB of RAM, and ideally a megabyte or two of flash storage.

32k/256k is the largest internal RAM/FLASH in an MCF51 chip, which would be a very simple proto board To get above 64k SRAM in Coldfire you have to have it external, in which case you might as well have DDR. And external Flash. Which means a complicated and expensive development board with lots of layers and often BGA chip mounting and so on.

Why not buy a Robot? It only has one serial port I can see, but it could be the easiest way to get something working. It gets you an MCF52259 Tower Module without having to buy a Tower to plug it into After you get it working you can get it WALKING. There seems to be TWO available for US$199. But only 64k on-chip SRAM and 512k on-chip FLASH.

Mouser Electronics - Be back soon...

> I'd like the option to run on real hardware rather than just in a simulator,

Why not run the simulator on some other embedded hardware? And to really annoy you, how about getting MAME running on a Raspberry Pi and running your code on that? I think there's a 68000 emulator in it somewhere.

Raspberry Pi • View topic - MAME

https://devtidbits.com/2012/11/26/mame-arcade-game-fun-with-a-raspberry-pi/

Tom

[TomE]

There are still non-Tower evaluation boards available, like the M54455EVB. But it is US$850!

There's another option you might consider.

You might be able to get an Altera or Xilinx development board with RAM and FLASH, and then load your CPU of choice as a synthesized core. I don't know if Freescale ever made any of their cores available for this, but I thought some of the smaller ones were. Does anyone know?

Or you could load a 68000 "opencore" onto it:

http://opencores.org/project,tg68

Or if you really want to use an old but elegant architecture, run an entire PDP 11/70, including disk drives:

http://opencores.org/project,w11,features

If you follow the links on the above page you'll find boards with the gate array, 256M of DDR3 RAM and 16M of Flash for US$99.

Tom

[johnames]

That actually sounds like an appealing notion, but could I pester you for the links to the boards you were discussing? All I could find was some links discussing boards with those specs, but they cost much more.

[TomE]

This is NXP's site, so I don't think it would be good manners to put direct links to other manufacturer's product, so that's why I didn't. The path was to click on the "w11,features" link, then the "Nexys2" one, and then on the "Arty Board Artix-7" one, which Google will find for you.

A note on Opencores. I was helping someone who was using one of the I2C Opencores to talk to an MCF51QE64, and was having problems. The core is 13 years old (2003) and still doesn't fully follow the I2C specification. It is fine when talking to simple chips like RTC or Flash, but not when using an MCF51QE64 as a slave, which has to clock-stretch. It is also very slow, adding a lot more clock cycles than really necessary, and not running at the expected bit speed. Nothing in the un-updated documented said this either.

https://community.freescale.com/message/453442#453442

So you might have an "interesting" time with CPU implementations too.

Tom