MPC870

As this is a Power PCX chip you may find that you can implement IEE1275 "Open Firmware" on the base level machine then run FreeBSD or a Unix on top of it providing you have the other resources available for the Unix like OS.

The Open Firmware level is a good system bring-up and debug layer that is able to assist you in booting quite complex other layers. Also, the required driver code for any of the plug-in cards you add can be in the plug-in card ROM (byte coded) ready to be compiled on a range of processors that support Open Firmware (important for future proofing while supporting old interfaces). You will find Open Firmware on Sun Workstation and Power PC's from IBM.

Paul E. Bennett wrote: : Martin Euredjian wrote: : :> I've been considering the idea of adopting the Freescale (a.k.a. Motorola) :> MPC870 processor for a board requiring ethernet, serial, USB (host and

:> One of the interesting things about this family of processors is that, I :> am told, they will run a version of Linux. This, to me, means that a huge

It's within the official CVS.

:> I'm looking for opinon as to the capabilities of these Freescale :> processors and, perhaps, suggestions for other devices I should be looking

Main competitior is, of cause, ARM7/ARM9. Faster ARMs compete against MPC82xx/PPC44x series PowerPCs.

MPC8xx are mature, solid chips with a nice architecture. Though they will work well for general purposes, it is in serial communication (20Mb/s HDLC) its' dual core (PPC+CPM) architecture will excel. For full speed 100Base-T you should aim at the 100MHz++ versions.

: As this is a Power PCX chip you may find that you can implement IEE1275 : "Open Firmware" on the base level machine then run FreeBSD or a Unix on top

There is no Open Source "Open Firmware" project. At least not for PPC8yxx. Open Firmware is a desktop issue. Use the U-Boot boot loader instead:

"Martin Euredjian" wrote in news:xIUYc.13941$ snipped-for-privacy@newssvr29.news.prodigy.com:

Not for nothing, but I found the IBM (now AMCC) 405GPr to be *far* easier to bring up. If you choose the 870 you will soon join the UPM haters club when attempting to use SDRAM. Unlike the MPC8xx family, the PPC4xx family (which can also run Linux) has a *real* SDRAM controller, set a couple of bits and say "go" - done. Read well the UPM documentation before committing to the 8xx.

Shudder.

The MPC555 and MPC56x have been by far the worst-documented microcontrollers I've ever encountered. Sure, there are aspects of the system architecture that are complex, but does the documentation need to refer to the same thing by three different terms? Does it need to change notational conventions almost on a chapter by chapter basis?

Motorola documentation was superb on the HC08/11/12 line and on the

pete

On Tue, 31 Aug 2004 06:15:57 GMT, "Martin Euredjian" wrote in comp.arch.embedded:

Atmel's AT91RM9200 is an ARM 920T with MMU so it can run regular Linux. In fact, I think Atmel has, or had, a distro you can download from their web site.

Among the on-chip peripherals are both USB 1.1 host and USB 1.1 device, SPI and I2C. Plus SDRAM, Compact Flash, regular flash, and others. Last I looked, some 32-bit micros had USB host on chip, but not many have USB device.

It might fit well if you need USB 1.1. If you need USB 2.0, you will probably need to go to external USB chips.

I can only agree that the MPC8xx processor family is a good fit. I suppose you can put the other comments about SDRAM interfacing into perspective (i.e. it should be doable).

Well, beware that Linux personalization to your system design can lead to project cost and delays. You might consider other kernels with real-time characteristics. There are a number of them, including eCos and the ABCD Proto-Kernel (on my web site), and a nomber of non open source alternatives.

- Thierry Moreau

CONNOTECH Experts-conseils inc.

Tel.: (514)385-5691 Fax: (514)385-5900

web site:

This is something of concern. I don't have time for complications. I'll read the UPM docs and comment.

Thanks,

I had a moment and took a quick look. This doesn't scare me that much. I've implemented FPGA-based SDRAM controllers from scratch. I can see the value in the flexibility offered, despite the complexity it adds. I can also see how some embedded guys could be horrified at the prospect of dealing with the UPM.

I'll have to dig further, at this point in time I am not to bothered by UPM.

"Martin Euredjian" wrote in news:a4oZc.14534$ snipped-for-privacy@newssvr29.news.prodigy.com:

Oh, it's not that, it's just that twiddling some signals on half-clock boundaries and others on quarter clock boundaries with the RAM words in a table listed top to bottom with time running down from top to bottom WRT to cycles gets complicated. The documentation is not overly clear, nor does the UPM diagramming tool seem to help (me at least) I spent a solid day getting the single beat read and write cycles to work (from scratch because I wanted to learn the UPM) and then wasted a week on the burst cycles. I finally gave up and used an app. note. When booting the 405GPr for the first time about 2 years later, I wrote a few simple bits to a couple of registers and I was done in about an hour of tweaking.

Fair enough.

The UPM can be quite a pest, but Freescale has an "UPM Programming Tool" that can be downloaded. I haven't tested it myself, but I assume it can at least help in getting things up and running a bit faster.

/Henrik

Henrik Johnsson wrote in news:ch6bj6$t94$ snipped-for-privacy@newstree.wise.edt.ericsson.se:

The version I used was less helpful than just reading the data book.