AVR Vs Analog Devices

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I was searching around the internet for microcontrollers that could do higher resolution A/D conversions than 10-bit & came upon the Analog Devices family of microcontrollers. They all seem to have 16/32-bit RISC processors (as compared to the AVRs 8-bit), run at speeds up to 40khz (as compared to the AVRs 16-20), all seem to have 12-bit ADCs (as opposed to 10-bit), also offer D/A converters (as opposed to none of the AVRs offering this feature)... so I just wanted to ask what the advantages were to using the AVR device? Are they just smaller? Or use less power? Or better optimized for integer math as opposed to floating point? I'm relatively new to programming microcontrollers, and have really liked my ATMega128 and ATMega1280... but after seeing those comparisons kinda wondered why the AVRs don't offer features to compete with these other devices?

- James

Last Edited: Tue. May 22, 2007 - 11:12 PM
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As far as I know, the AD chips are full DSPs. Expect them to be a lot more expensive.

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

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ka7ehk wrote:
As far as I know, the AD chips are full DSPs. Expect them to be a lot more expensive.

Jim

As will be the programming software, development equipment and, possibly the learning curve.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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You might as well ask yourself:
Why doesn't my bicycle run as fast as that road-racing machine?
They both have two wheels...

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DSP should have X and Y address spaces for FIR coefficients and code, but these address spaces are small... filters are short loops that run fast. Instruction set has 'add with saturate to ffff instead of wrapping back to zero' and 'multiply and accumulate' special instructions. AVR is more of a 'classic' general purpose cpu than a dsp. All this is just opinion, not dogma.

Imagecraft compiler user

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The analog devices devices he's talking about are the ADUC series of micros. These are aimed at apps requiring better analog performance and you'll find the price tag reflects this. I use an aduc834 which is about $15usd each, is not faster than an AVR but ends up cheaper than an AVR and a 24bit ADC. Your AVR is a more general purpose part - cheap and cheerful and does 99% of what you need.

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Thanks for all of your comments... and yeah, I was just looking at something like this: http://www.analog.com/en/prod/0,,762_0_ADUC7026%2C00.html for $8.80. It seemed pretty comparable to the ATMegas... just higher res ADCs, faster processor, DAC available, etc... I doubt I could handle the learning curve on another brand chip anytime soon... I just kinda wish that Atmel offered some devices with similar features for people that needed them... even if they cost twice as much.

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Quote:

...faster processor...

How would Yoda say it: "Not a faster processor does a higher clock-speed make." or something like that.

Lee

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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The ADuC 7000 series are ARM7 devices. Free software is available:
YAGARTO
WinARM

JTAG programmers/debuggers are available at reasonable prices.

If you are in the high-end AVR ballpark, you should consider moving to ARM. Might be a good idea to learn the AVR really well first, though, so you are better prepared for the ARM's learning curve :)

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AVR is not a Religion, it's

A way of making efficient devices at
V ery
R easonable cost

So if you need some features, not available in AVR family, you can freely go for other micros as well :)

Regards,
Gintaras

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The ADuC ARM series is very nice to work with actually. You don't even need a programmer, just a serial-cable (USB->Serial). All devices have built in boot-loaders with auto-baud.

If you need to do better A/D-converter stuff (higher quality sample and more calculations), an ARM is usually a better choice than an AVR. This applies performance wise. Of course most AVRs are cheaper than any device in the ADuC-series.
Power-wise, the ARMs often win when counting milliwatts per MIPS. The clock on the ADuC can be scaled by software, as they can on the newer AVRs.

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Well, how about considering that AVRs are NOT intended for image procesing, sound coding/decoding etc, whereas DSPs are.

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

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ADuC's are in fact two different families: ARM powered one an MCS-51(8051) powered the other one.

My advise is: learn how to program AVR's, specially M128/1280. Then move to ARM based ADuC. Don't spend any time with 8051 derivatives (also they are pretty good uC). For analog signal processing, the devices you told are really a good choice: 40 MHz CPU clock, 1MSPS @ 12Bits (up to 16 channels), and 32 bit processor, enough for many 32 bit math, like it seems to be the usual work for this uC.

JTAG for ARM is really cheap (even more than for AVR's), and there is plenty of well developed free software and support tools. ARM 7TDMI is a really extended and well known CPU core, thus probably many things that exist had been done on this processors.

Not easy to program for a novice, though. Thus better you learn how to program an "small uC" like M128. Then any ARM based uC would be not "too big" to learn.

Guillem.

Guillem.
"Common sense is the least common of the senses" Anonymous.

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Analog Devices ADUC70XX family is created for the best analog performance (a/d accuracy & precision). Then if your application require this features, ADUC70XX is the right device for you. Remember if you need some logic glue ADUC70xx has a PLA (a small PLD) integrated. Also it has a DAC (I think not present in AVR devices)

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I'd like to correct runblade's post: there are AVR devices with DAC - AT90PWM series

Gintaras

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gintaras_bar wrote:
I'd like to correct runblade's post: there are AVR devices with DAC - AT90PWM series

Gintaras

Thanks Gintaras! Never stop learning!

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Why doesn't Atmel make ARMs? They do!

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Quote:
Why doesn't Atmel make ARMs? They do!

Well, atmel DOES make em. Only they are named SAM something. They make arm7, arm9 and even will make arm11.

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

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Hi,

I bought both AVR's and Analog Devices micros (butterfly and $30 ADUC miniboard) and designed them into the same project, just to see what the differences where (AVR169 vs AD7020),

1) The ADuc7020 uses alot more power then AVR.
2) The ADuc7020 has a higher performance A/D, but also requires more attention to load resistance, usually you need an opamp in front of the A/D inputs.
3)The Aduc7020 is much better at floating point/integer math, has 8K of RAM too, which is nice.
4)for starting out the Analog devices was much easier to get up an running with the IAR workbench (C complier), I hooked out the 7020 to an accelerometer and got data read in and printed to the screen in a few hours (all in C).
5)The ADuc7020 has a better internal RC clock, temperature sensor, DAC output, PLD logic, but no LCD interface like the AVR's have.
6)THe Aduc7020 has a much higher sleep current then the AVR.
7)The Aduc7020 requires a voltage regulator to work off a lithum battery whereas the AVR can run directly off the battery.

thats about all I can think of, both of them are sitting in front of me so if you want more info let me know, updated C code and downloading to them is the same effort on either.....

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Quote:

3)The Aduc7020 is much better at floating point/integer math,

If a standard x51 core, even single-cycle, I'd question that one based on the TI/MAX2000 benchmarks. >>But<<, you were comparing a Butterfly which runs at a quite modest clock rate, right? What speed were you running the Butterfly at?

Lee

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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theusch wrote:
Quote:

3)The Aduc7020 is much better at floating point/integer math,

If a standard x51 core, even single-cycle, I'd question that one based on the TI/MAX2000 benchmarks. >>But<<, you were comparing a Butterfly which runs at a quite modest clock rate, right? What speed were you running the Butterfly at?

Lee

the aduc7020 has a 32 bit ARM processor

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Quote:

the aduc7020 has a 32 bit ARM processor

Ooops; my memory failed me--I thought that ADUC7x & ADUC8x were all the x51-core. The ADuC7xxx are the ARM core, as you well knew. ;)

Lee

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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A big factor, perhaps the biggest factor, is that with any other uC, you will not find a site as helpful as AVRfreaks.net for AVR.

To me AVR represents the most competitve 8 bit uC around. If you need more processing power then that just means you should get a 16/32 bit uC.

Peripherials wise, AVR is a comprimise, it has enough to satisfy 90% of the people 90% of the time.

If peripherials is all you want then I think you will have a hard time finding something better than the cypress PSOC.

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Je, je. Cypress announces new ARM based (256K Flash, 64K RAM, 16bit 40KSPS ADC,...) PSoC, since the cores of actual ones are 'small' (16, up to 32K Flash, 256 bytes RAM). Thus for bigger applications where one needs something like M64/128/256, they can't compete.

For anything like ATtiny, PSoC have the best peripherals and flexibility possible in the market.

Guillem.

Guillem.
"Common sense is the least common of the senses" Anonymous.

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Guillem Planisi wrote:
Je, je. Cypress announces new ARM based (256K Flash, 64K RAM, 16bit 40KSPS ADC,...) PSoC, since the cores of actual ones are 'small' (16, up to 32K Flash, 256 bytes RAM). Thus for bigger applications where one needs something like M64/128/256, they can't compete.

For anything like ATtiny, PSoC have the best peripherals and flexibility possible in the market.

Guillem.


With a more powerful core PSoCs are looking more useful. It's too bad that they still haven't released one with CAN, though. I'd probably be sold if they could do that, and put it in a nice small package.

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Cypress sales representative was at my company yesterday, and commented me that probably in two or three weeks there will be some technical documentation about the new ARM products. Probably I could see what other peripherals came with it. Specially 16 bit ADC's are interesting to me, but also CAN would be welcome.

Depending on price an peripheral set/capabilities, they can be a really powerful alternative to any other uC.

Guillem.

Guillem.
"Common sense is the least common of the senses" Anonymous.