Linux To Gain Another Chip Family

An anonymous reader submits "Freescale will unveil the first ColdFire processors ever to include a memory management unit (MMU), and therefore able to run full-scale Linux, this week at the Embedded Processor Forum in San Jose, Calif. The chips cost $17 - $25, and are used mostly in industrial control and factory automation. Simultaneously, Freescale tools subsidiary Metrowerks announced plans to offer Linux development tools for Coldfire chips, which previously had been restricted to running uClinux due to the lack of an MMU."

Comments

New Amigas

[Amiga Lover]

These chips, distantly related to the 68k motorolas, were once touted as a possible upgrade path for new Amigas in the mid 1990s. Hopefully with these new ones, the more modern AmigaOS4 can be ported to them, and continue the heritage. At the moment the only stock available is AmigaOne G3, G4 and mini-itx PPC boards, which are artificially inflated in price by the apple/ibm/motorola consortium.

Re:New Amigas

[Jeff DeMaagd]

which are artificially inflated in price by the apple/ibm/motorola consortium.

It appears that way when in reality, that probably is an exercise in comparing bananas and oranges.

Development Evaluation / Reference Design boards are generally higher in price because of their volume, and the fact that they have different levels of support, often times, software, documents and engineering support is available to them for this type of product. Products intended for a slightly different market, the embedded market, are often slightly cheaper but don't always fit the "standard" form factors like ATX and ITX, but they weren't meant to be used as personal computers, so that point is moot, although it would probably help prices and cut development costs a lot.

The idea is that a prospective manufacturer would buy the Devel board to test the capabilities of the overall system. When they want volume, they take the reference design as a basis for their own fabrication and and make it in volume, but often for proprietary form factors to fit a very specific task.

One thing I noticed is that reference boards for Intel and AMD chips often cost a little more than those for RISC chips. If the ARM board costs $600, a similar embedded reference board for an x86 chip often costed $700 to $800. The difference here is that there are plenty of consumer boards available for x86 systems, but not RISC systems, so this is where the RISC boards look expensive.

Why is this so important?

[raahul_da_man]

I thought I knew which processors were important in the embedded world. What exactly is Coldfire, and why does it matter compare to ARM and Motorola's offerings?

I realise that Yet Another Embedded Processor that can run all of linux is a good thing. I just don't see why that is important, since the difference between embedded and desktop processors has been diminishing sharply.

motorola

[Coneasfast]

freescale is a subsidiary of motorola, here is homepage for coldfire.

Great, I can use them

[Orion Blastar]

I want to build a low cost Computer Automated Dispatch system with just the basics for low income firehouses, police stations, and hospitals. This chip might just fit the bill. I was going to go with Transmeta or a low end X86 processor.

Re:Great, I can use them

[DAldredge]

Mission critical systems and first generation chips are not a good match.

on chip stuff

[baryon351]

Other key features of the new MCF547x and MCF548x ColdFire processors include on-chip FPU and eMAC

Dammit apple, I just bought a brand new eMac only months ago, and now they're putting them on-chip for under $30!

ColdFire is *already* supported in Linux

[gergoid]

I added support for ColdFire processors to Linux years ago. This won't be new. It was added to Linus kernels in the 2.5 series, and is fully supported in the 2.6 kernels for all the older ColdFire parts (5206, 5249, 5272, 5282, 5307, 5407). Ofcourse the older parts did not have an MMU.

Look under the arch/m68knommu branch for all the architecture support...

Re:ColdFire is *already* supported in Linux

[gergoid]

Wrong. The ColdFire's run the same ISA as the m68k family. They are just a reimplemtation of the their ISA. Go look at the code under arch/m68knommu in the 2.6 linux source. You will find my name next to all the ColdFire bits.

Re:ColdFire is *already* supported in Linux

[pyrrhonist]

That was put there for 68ks such as the 68EC060 which had no MMU, not coldfire

Yeah! Way to serve the guy who wrote the support for the earlier ColdFire chips! Greg was obviously talking out his ass and doesn't know anything about the code he wrote. IT'S ON!

/*
* crt0_ram.S -- startup code for MCF5206 ColdFire Arnewsh board.
*
* (C) Copyright 1999-2002, Greg Ungerer (gerg@snapgear.com).
*

Re:Metrowerks

[Rosco P. Coltrane]

Huh? Metrowerks produces apple development tools, and they dabble in linux/embedded development tools. I'm pretty sure that Metrowerks is not a freescale subsidary. See for example this PR.

1 - Metrowerks is a Freescale "early tester", i.e. they get Freescale stuff first

2 - Metrowerks acquired Lineo and their Embedix Linux offering a while ago, and offer it as one of their core products. Therefore, they more than "dabble" in Linux.

FYI Freescale is the old Motorola SPS group

[cacheMan]

This isn't some fly-by-night chip maker.

PowerPC is as cheap as ColdFire

[Wesley Felter]

First, let's compare apples to apples. These new ColdFire processors run at 266 MHz and cost $20-27. The 266MHz PowerPC MPC5200 (also from Motorola) costs $27.

Even the desktop-class PPC 750s and 74xxs aren't expensive if you buy them in volume. The AmigaOne is expensive because it is a niche-of-a-niche product, not because Moto is ripping people off.

Huge Difference

[bsd4me]

There is a really big difference between embedded processors and mainstream CPUs.

The biggest is that power consumption is really important in the embedded world. Sometimes you can only get so much current to a board, or you can't run fans.

Typically, embedded processors can run without support chips. Many have built in memory controllers and I/O.

Another thing is the MMU. A lot of embedded processors have MMUs (I think most of the PPC ones do), but OS support for them is a bit lacking (or it was until recently). But at times, the MMU can get in the way

IMHO, I would never run linux in an embedded product, other than simple internet appliances or where realtime isn't required. Commerical RTOSs like VxWorks really are worth it for most embedded applications.

ColdFire is 680x0, nearly

[r00t]

ColdFire was created like this:

1. start with 680x0
2. rip out the bloat (MMU, fancy FPU, etc.)
3. redo the opcode-to-binary mapping

Often you can use 680x0 assembly code on
a ColdFire chip, though you'll need to run
it through a ColdFire assembler. You can't
just grab a binary.

Re:This isn't a great as it seems

[Anonymous Coward]

Don't click that link. If you check your status bar, it's "http://www.google.com/url?sa=D&q=http://www.peopl esprimary.com/?n=Sarojin", which redirects to http://www.peoplesprimary.com/?n=Sarojin, not a Google search. The page is nasty

VxWorks is crummy

[r00t]

Their shell is an abomination. Their filesystem
is plain old DOS FAT, optionally with an
incompatible long-filename feature. The "mount"
command (function? all the same...) is totally
defective, doing some kind of dumb text substitution
instead of real mount points. Memory support is
terribly limited -- is 32 MB enough for you?

For the cost of VxWorks, you can get a bit of
extra memory for running Linux. You'll also save
on development costs that way.

If you'd really prefer a tiny OS designed for
strict real-time from the start, use eCos.
It's free even.

Another chip *family*? No.

[DdJ]

Another chip family? No, unless you think Intel XScale and TI OMAP are in different chip families. The ColdFire chips are just another example of the m68k family, like the DragonBall chips are.

This underscores the need for software freedom.

[jbn-o]

Innovation like this underscores the need for relying on free software (or, put differently, the problem with relying or recommending non-free software). It's an easy trap to get into when you use an i386 GNU/Linux distribution (as most GNU/Linux users do, I suspect) because there are so many opportunities to get hardware that only fully work with non-free software (like nVidia video cards that require non-free kernel driver software to operate fully). When you become dependent on non-free software you lose portability which prevents easily moving to interesting hardware like this one. Non-free video and audio codecs are similar; if you base your work on some Microsoft library for decoding audio or video you won't easily be able to read those files on a non-i386 platform.

Software proprietors won't supply the wide range of support the free software community does. Software proprietors won't give you the power to provide your own support or buy it from programmers and sysadmins in the free marketplace.

What's so "u" about uCLinux?

[Doc Ruby]

uCLinux is a port of Linux to CPUs without an MMU. Without an MMU, the chips don't support the convincingly simulated parallelism of fork(), rather just the nominally similar (blocking) vfork(). What other compromises must an application concede when running under uCLinux, rather than a "full" Linux kernel?