PIC vs AVR vs ARM
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From: rickman on 3 Oct 2006 15:14 steve wrote: > Buddy Smith wrote: > > > I thought so too, but the products from luminary micro > > (luminarymicro.com), discussed in this newsgroup recently and in Circuit > > Cellar, have changed my mind. > > > > They make ARM CPUs with very little RAM and flash, on the cheap.... they > > say less than one dollar in 10k quantities (from an advertising spiel) > > > > ttyl, > > > > --buddy > > yes but they are very high power, I think 10x the power of the AVR at > 1Mhz, if I remember correctly I think you are mistaken. If you compare the ARM MCUs at the same frequency that the AVR runs, you will see that the power for the ARM can be lower than for the AVR. That is one of the big reasons that we recently used an ARM in a new design in place of the AVR which we have typically used in the past. It may be that in the smaller configurations an AVR can run at much lower power, but if you are comparing apples and not oranges, I think the ARM chips can keep up with most 8 bit parts in terms of power.
From: rickman on 3 Oct 2006 15:23 We have used AVR MCUs in many of our products and were very happy with them. On a new project I decided to take a look at the ARM MCUs to see if we could branch out from some of the limitations of the AVR. We did a very exhaustive comparison between the various ARM processors and the ATmega128 and found that the ARM chips were generally lower power, lower cost and fit in a smaller footprint on the board. We also were able to use a much smaller crystal. The ARM we chose for this project was the AT91SAM7S64 due to its combination of low cost and low power. The Philips parts seem to run a close second and may even beat the Atmel SAM7 parts depending on exactly the combination of features you need. If you don't need the lowest power then the other brands of ARM chips could be considered, ST Micro STR7, TI TMS470 and Analog Devices ADuc7 among others. Did you check out the feature comparison chart at www.gnuarm.com? Click to the Resources page and scroll down to the ARM chips section where you will find three different links for the comparison chart. Jason wrote: > To add to this question, I've been doing mostly AVR work and I'd like to > branch into ARM. I had planned on just picking up some of Atmel's ARM > gear, but would anyone suggest any other first leap friendly ARM procs? > The Luminary has already been mentioned and seems interesting. > > > Jason > The place where you made your stand never mattered, > only that you were there... and still on your feet > > > Miem wrote: > > Hi All, > > > > As an amateur embedded circuit player, I have used couple of AVR and > > PIC microcontrollers in the past. > > > > In these days it is not to hard to find small, ARM based ready to use > > embedded boards under $100. They seems to have faster clock speed then > > most of the AVR and PIC boards. > > > > Can anybody shortly compare ARM with PIC ad AVR interms of (a) > > performance (b) software support (c) price? > > > > Regards, > > > > Miem > >
From: steve on 3 Oct 2006 16:25 rickman wrote: > I think you are mistaken. If you compare the ARM MCUs at the same > frequency that the AVR runs, you will see that the power for the ARM > can be lower than for the AVR. Depends alot on how fast you run them, but the ARM's always use more power per frequency, the AVR is an 8 bit device that can operate down to 1.8 Volts the ARM is a 32 bit device that requires 3.3 Volts, so it obvious who is going to use less power (assuming all else being equal, process, I/O, RAM, FLASH etc). looking up a couple datasheets Analog Devices ARM 7021 7.2mA(a)1.3 Mhz(typical) Atmel Atmega164 .4mA(a)1.0 Mhz(typical) At higher speeds the ARM's don't have as bad mA/ Mhz ratio Luminary Micro LM3S101 35mA(a)20 Mhz (typical, running out of SRAM, no active peripherals) Analog Devices ARM 7021 33mA(a)41 Mhz(typical) That is one of the big reasons that we > recently used an ARM in a new design in place of the AVR which we have > typically used in the past. > Which ARM and AVR did you compare? At what speed? > It may be that in the smaller configurations an AVR can run at much > lower power, but if you are comparing apples and not oranges, I think > the ARM chips can keep up with most 8 bit parts in terms of power. you can make the argument for math intensive applications the ARM can execute it much faster, thus only needs to be on for a much smaller period so less total power that way, was that how you did the analysis? The AVR's also have much better power down and sleep mode currents, which may or may not be important for your application.
From: pbreed on 3 Oct 2006 16:35 Take a look at: http://www.netburner.com/products/core_modules/mod5213.html For $99.00 a 32 bit dev kit. Faster and more capable than most of the small ARMs. Paul
From: Mike Silva on 3 Oct 2006 17:10
rickman wrote: > We have used AVR MCUs in many of our products and were very happy with > them. On a new project I decided to take a look at the ARM MCUs to see > if we could branch out from some of the limitations of the AVR. We did > a very exhaustive comparison between the various ARM processors and the > ATmega128 and found that the ARM chips were generally lower power, > lower cost and fit in a smaller footprint on the board. We also were > able to use a much smaller crystal. What do you mean, "a much smaller crystal"? |