Forums

What is the lowest-power 32-bit MCU?

Started by Ghazan Haider November 14, 2004
Specifically which MCU that can boot Linux has the lowest operating
power? I imagine it would be a low-clock arm, I intend to lower the
clock further for my application. I'm hoping for less than 15mW at 3V,
more like 5mW if at all possible. LCD controller preferable but beside
that and IO lines no other options required.

Has any company come out with low-power series of 32-bit MCUs? I
couldnt find them targetting any such market at the usual places,
atmel, sharp, arm website.
"Ghazan Haider" <ghazan.haider@gmail.com> skrev i meddelandet
news:1ad1e8b9.0411140015.447c645@posting.google.com...
> Specifically which MCU that can boot Linux has the lowest operating > power? I imagine it would be a low-clock arm, I intend to lower the > clock further for my application. I'm hoping for less than 15mW at 3V, > more like 5mW if at all possible. LCD controller preferable but beside > that and IO lines no other options required. > > Has any company come out with low-power series of 32-bit MCUs? I > couldnt find them targetting any such market at the usual places, > atmel, sharp, arm website.
Low clock frequency and low voltage is what you need. The AT91M40800 is the Atmel candidate. ARM7TDMI and can run on 1.8V and the design is static, so you may want to clock it down to 10 MHz, for 0 waitstate operation from std flash. There is no SDRAM controller on this, so you need to use SRAM. -- Best Regards, Ulf Samuelsson ulf@a-t-m-e-l.com This is a personal view which may or may not be share by my Employer Atmel Nordic AB
In article <1ad1e8b9.0411140015.447c645@posting.google.com> ghazan.haider@gmail.com (Ghazan Haider) wrote:
> >Specifically which MCU that can boot Linux has the lowest operating >power? I imagine it would be a low-clock arm, I intend to lower the >clock further for my application. I'm hoping for less than 15mW at 3V, >more like 5mW if at all possible. LCD controller preferable but beside >that and IO lines no other options required. > >Has any company come out with low-power series of 32-bit MCUs? I >couldnt find them targetting any such market at the usual places, >atmel, sharp, arm website.
A cynic is a man who think courtship is the first in a series of steps leading to divorce. -- Lady Chatterly "Do you think that Alexander Mulligan, a super-eco commune resident who takes a break from his regular commune duties and hikes all the way into Bellingham every day in order to use Bruce Burhans' internet account so he can engage in trivial bickering, is also a woman named Lady Chatterly", who does exactly the same thing?" -- Tom
> Low clock frequency and low voltage is what you need. > The AT91M40800 is the Atmel candidate. > ARM7TDMI and can run on 1.8V and the design is static, so you may want to > clock it down to 10 MHz, for 0 waitstate operation from std flash. > There is no SDRAM controller on this, so you need to use SRAM.
I've been debating with myself on how low in MIPS can I go. The applications are not clear yet, 33MIPS would be terribly nice for a rudimentary graphic windowing screen on an LCD. 18MHz takes 18mA or something like that for ARM, but I also found out LCD screens take far less current than I thought.... 20mA for 320x240 or so. That gives me room. Now if SRAM and flash take 60mA or less in constant use, I'm golden. Its funny how some specs are insufficient, too many arm vendors claim low power without specifying it anywhere but the ELECTRICAL CHARACTERISITCS deep down the datasheet, and nowhere at all for most LCD vendors. I've had tough time for SRAM power specs, and solar panel vendors usually dont even have a datasheet. As for the MCU, I'm looking at atmel and cirrus unless someone else claim lower specs.
Ghazan Haider wrote:

> Specifically which MCU that can boot Linux has the lowest operating > power? I imagine it would be a low-clock arm, I intend to lower the > clock further for my application. I'm hoping for less than 15mW at 3V, > more like 5mW if at all possible. LCD controller preferable but beside > that and IO lines no other options required. > > Has any company come out with low-power series of 32-bit MCUs? I > couldnt find them targetting any such market at the usual places, > atmel, sharp, arm website.
This is also a matter of additional junk hardware. Using a hub instaed of a switch increases the number of messages to be processed on the ethernet. A simple ethernet controller on the bus increases the load proportional to the number of packets, whereas a busmaster ethernet controller just makes one interrupt per message. The same applies for all peripheral devices. Rene -- Ing.Buero R.Tschaggelar - http://www.ibrtses.com & commercial newsgroups - http://www.talkto.net
> Specifically which MCU that can boot Linux has the lowest operating > power? I imagine it would be a low-clock arm, I intend to lower the > clock further for my application. I'm hoping for less than 15mW at 3V, > more like 5mW if at all possible. LCD controller preferable but beside > that and IO lines no other options required.
Don't forget the dynamic power consumption. Charging and discharging a capacitor costs W=CU**2 Joule, which is P=fCU**2 Watt. If you take some real life values, then the capacity of a trace is 10pF (probably much more), the I/O voltage 3.3V and toggling frequency may be 10 MHz. Under these conditions, one such trace alone costs 1mW. If you toggle 32 data lines and some address lines, then your system consumes easily 50mW. Therefore take a device with internal memory or at least built-in caches. Michael
Lady Chatterly <ghazan.haider@catcher.in.the.rye> wrote in message news:<d82c21d.ab6a7387@ausi.com>...
> A cynic is a man who think courtship is the first in a series of steps > leading to divorce.
(1) What did you mean? (2) How is this related to the comp.arch.embedded? (3) Why is my name in your email address?
On 15 Nov 2004 10:14:21 -0800, ghazan.haider@gmail.com (Ghazan Haider) wrote:

>(1) What did you mean? >(2) How is this related to the comp.arch.embedded? >(3) Why is my name in your email address?
It's someone's software trying to emulate a human -- a kind of eliza program thing. You can try eliza at: http://psych.fullerton.edu/mbirnbaum/psych101/Eliza.htm But that's about all it is. Just kill-file it. Jon
"Jonathan Kirwan" <jkirwan@easystreet.com> wrote in message
news:a2thp05utnj6h3nu86j300oa41dmbotkne@4ax.com...
> On 15 Nov 2004 10:14:21 -0800, ghazan.haider@gmail.com (Ghazan Haider)
wrote:
> > >(1) What did you mean? > >(2) How is this related to the comp.arch.embedded? > >(3) Why is my name in your email address? > > It's someone's software trying to emulate a human -- a kind of eliza
program
> thing. > > You can try eliza at: > http://psych.fullerton.edu/mbirnbaum/psych101/Eliza.htm >
Eliza was OK, but I liked Racter better. More than 15 years ago, I think. The best thing to get Racter started was to ask him to tell a story. I distinctly remember the phrase "a millisecond in a station wagon is spooky". ILSHIBAMF