Forums

Speed/power tradeoff in ARMs

Started by rickman March 19, 2007
I am looking a a project for a portable device, not a lot different
from a PDA in terms of design.  I would like to compare some of the
ARM9 processors for performance vs. battery life to see just how much
horsepower is compatible with a moderate battery size.  I see that
Atmel and Philips have new parts out.  The new TI parts don't look
like they are optimized for power and I don't think the ST parts are
either.

Marvell seems to have the data sheets for the StrongARM parts under
NDA.  That seems odd to me.  Did Intel do that as well?  I think I
will shy away from Marvell just because of that.

Any good devices out there that I may have missed?

rickman wrote:

> I am looking a a project for a portable device, not a lot different > from a PDA in terms of design. I would like to compare some of the > ARM9 processors for performance vs. battery life to see just how much > horsepower is compatible with a moderate battery size. I see that > Atmel and Philips have new parts out. The new TI parts don't look > like they are optimized for power and I don't think the ST parts are > either. > > Marvell seems to have the data sheets for the StrongARM parts under > NDA. That seems odd to me. Did Intel do that as well? I think I > will shy away from Marvell just because of that. > > Any good devices out there that I may have missed?
Well, you'd want to at least look at the AT32UC3A0512 / AT32UC3A1512, as well as the Atmel ARM9s. With ESC looming, I'm sure more info is about to hit the streets. -jg
"rickman" <gnuarm@gmail.com> skrev i meddelandet 
news:1174358182.814685.63100@b75g2000hsg.googlegroups.com...
>I am looking a a project for a portable device, not a lot different > from a PDA in terms of design. I would like to compare some of the > ARM9 processors for performance vs. battery life to see just how much > horsepower is compatible with a moderate battery size. I see that > Atmel and Philips have new parts out. The new TI parts don't look > like they are optimized for power and I don't think the ST parts are > either. > > Marvell seems to have the data sheets for the StrongARM parts under > NDA. That seems odd to me. Did Intel do that as well? I think I > will shy away from Marvell just because of that. > > Any good devices out there that I may have missed? >
If you need an LCD controller, then you have four basic choices from Atmel. * AT91SAM9261S * AT91SAM9261 * AT91SAM9263 On top of that you could look at * AT32AP7000 (AVR32 based) You then need to figure out screen size. The AT91SAM9261 has built in framebuffer for QVGA at 16 bpp (160 kB) This gives you high performance, if you draw in the internal buffer or low power consumption, since display referesh draws comparatively little power. If you accept single buffer or 8 bpp, then you get the best of two worlds. My gut feeling says that this is the right chip. The SAM9261S is pincompatible but without the large framebuffer (16 kB), which will reduce performance (display refresh eats bus cycles from SDRAM) and also increase power consumption. It is of course cheaper than the SAM9261. The SAM9263 is the preferred choice for VGA or higher resolution. It has a dedicated 16 bit bus to a PSRAM allowing refresh to occur without interference on main CPU SDRAM bus. A 2D accelerator and a memory to memory DMA allows you to draw on the main 32 bit bus, and do a quick copy to the secondary bus allowing you to spend maybe 90% of bandwidth on display refresh. (Assuming no Video) It has Ethernet, for what it is worth in a PDA. AT32AP7000 LCD is similar to AT91SAM9261S but has nice features if you want video and a high speed USB device. It does not have a USB host controller but has Ethernet. All the ARM chips have full speed USB device and dual port USB host. If you need WinCE, forget the AVR32. The NXP part has no LCD controller from what I have seen. -- Best Regards, Ulf Samuelsson This is intended to be my personal opinion which may, or may not be shared by my employer Atmel Nordic AB