Open, embedded ARM processor for handheld test equipment?

I'm not sure why you'd pick linux for something that, at least in the data acquisition stage, has hard real-time requirements. My experience has been that linux gets in the way of real-time processing---at least until you know a lot more about it than I do now.

The Triton LP module is about 1.4 x 2.8 inches. You're going to have to be a darn good PCB layout person to design a smaller module that will run Linux. Better get friendly with prototyping on BGA modules also! ;-)

The GumStix modules are a bit narrower, but I haven't worked with them.

You might try prototyping with the Triton or GumStix, then when you have solved the software and other hardware problems, you could try shrinking the system.

Mark Borgerson

Me thinks you are describing some mass-produced PalmOS or WinCE Handheld/PDA, or an Apple iPod, for which Linux ports already exist. (Not sure what cpu is used on iPods.)

Roberto Waltman

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The linux (and X-server and python and all that userspace stuff) are just for the gui; the real-time stuff will be managed by an FPGA. There's no way I'd try and do anything with hard real-time needs under linux :)

We do this sort of thing all the time, because a lot of the hardware we design has to be worn on the head of a rodent :) And BGA prototyping isn't that expensive anymore, either, thanks to the proliferation of PCB assembly houses (like eTech-WEB) that will do one-off placement for you. Otherwise we could never attempt this! ...Eric

Roberto,

In my experience there's a big difference between "some hardcore engineers managed to burn an image into the device's flash and get it to boot" and real vendor / toolchain support. I guess that was part of the hope in going with something ARM-based -- the core ISA is popular enough that there are a wide variety of people hacking on / supporting the gnu toolchain.

...Eric

The LPC3180 looks interesting, especially if you need hardware floating point. Available in ones from Digikey.

Needs external flash and SDRAM.

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John Devereux

Another option would be a PPC based CPU, like Freescale MPC5200. But while there are plenty of CPU options (I don't know if unix capable), the bigger issue you may be facing is the display interface. If you are after something VGA sized and above, be prepared to discover there are no longer any single-chip devices being manufactured...

Dimiter

------------------------------------------------------ Dimiter Popoff Transgalactic Instruments

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snipped-for-privacy@mit.edu wrote:

I'm working on a similar project (mini spectrum analyzer and signal generator) - though not battery-powered - and I'm using a Virtex-4 FPGA with an embedded PowerPC core. However, the clever bit here is that I can route my digitized signal through "hardware" based processing before the CPU core ever needs to touch it.

I agree with other posters that you should have a very good reason for

- and understanding of the limitations inherent in - choosing Linux for this project.

How fast does it have to be? ST, Atmel, Sharp and Philips all have _reasonably_ frisky ARM parts, and they're pretty free with information. Lots of hobbyist projects built around the Atmel and Philips parts, in particular - though if you need color LCD, Sharp is a simpler route.

You may want to check out the ARM9 + FPGA module at

Runs Linux on the AT91RM9200 and the FPGA can be used for LCD. The AT91RM9200 is well supported by the Linux Kernel and I/O technology has extensions for the FPGA programming in Linux/U-Boot.

For toolchain,boot,linux and root file system, you can use my Buildroot system at ftp://at91dist:distrib@81.80.104.162/ -> AT91 Third Party -> Linux Host -> Buildroot

--
Best Regards,
Ulf Samuelsson
ulf@a-t-m-e-l.com
This message is intended to be my own personal view and it
may or may not be shared by my employer Atmel Nordic AB

Well, I've done some linux work in the past, but could you perhaps expand a bit on what other limitations you might see? I'm not really planning on having either the OS nor the userspace apps need anything appropaching "real-time", and the availability of a lot of pre-existing software is a bigger deal for me.

...Eric

I suggest you look on google for "PXA270 developer manual" first result should give you access to the infromation you require from intel site. i cannot see anything for the PXA300 :(

there are many cheap single board designs for PXA 270 aka Bulverde - there are as yet few for PXA 300

Mark