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at91 choices for my application...help

I am trying to decide what flavor of the AT91 series ARM ucontrollers to use for a low cost, low volume product.

I need 4 channels of 10 bit ADC, and 4 channels of 12 bit DAC (though I could get by with two 10 bit and two 12 bit), hardware PWM would be nice, but I guess I could do it in software.

On the one hand, the AT91M55800 sounds attractive with its ADC, DAC (though not enough channels or resolution), PWM, SPI, and large memory address. It is quite a large package (176 pin TQFP), but is probably hand solderable in low volume (25 to 50 units) since I have hand soldered lots of 208 pin spartan II packages. I don't really need all the extra I/O though. The eval board is $250 at digikey.

Then there is the AT91M40008 which has 256k x 8 sram and operates at 60mhz. This would make for a somewhat simpler board layout since I would not need external sram, just flash. This chip does not have much in the way of periph. though, not even an SPI to talk to the DAC. It costs about the same at the

55800, and the eval board is $198 at digikey.

Last of course would be the AT91RM9200 which sounds really cool, but is probably way overkill for this product and the eval board and development kit is $5000 (not sure if you can just get an eval board, or if that by itself would be useful). The chip itself does not cost much more than the others though....

I am really only familiar with atmel's avr series, but in this ap, an 8 bit ucontroller just does not have enough hp. I am leaning toward the 55800 with external sram, flash (and hopefully a compact flash interface) and a 2 to 8 channel DAC. Suggestions?

Thanks,

Rick

Reply to
Rick
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for

quite

packages.

probably

I'd go the AT91R40008 way, with external analog I/O. The SPI master (or I2C/TWI) is not too difficult to provide for in software (mail me if you have problems). The chip is electrically pretty quiet to the outside when run from internal RAM, also it runs with relatively little power. Actually the RAM is 65 kwords of 32 bits.

There are three timers on chip, each capable to provide the PWM.

The maximum external addressing capability is 4 blocks of 16 Mbytes each, to a total of 64 Mbytes.

HTH

Tauno Voipio tauno voipio @ iki fi

Reply to
Tauno Voipio

for

Have a look at the Philips LPC2100 ARM chips. You'd have to use an external DAC but otherwise I think that the LPC2124 has everything you need:

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Availability seems to be a problem at the moment, but that should improve.

Leon

--
Leon Heller, G1HSM
Email: aqzf13@dsl.pipex.com
My low-cost Philips LPC210x ARM development system:
http://www.geocities.com/leon_heller/lpc2104.html
Reply to
Leon Heller

I think I have heard this before...

:)

- Ville

--
Ville Voipio, Dr.Tech., M.Sc. (EE)
Reply to
Ville Voipio

for

quite

packages.

probably

You said nothing about your memory requirements or processing speed. That is normally the most important part of an MCU. For a low volume product I would not go with a chip, but rather a board. There must be tons of boards out there with a 32 bit micro with ram/rom and analog IO. Think of all the NRE savings that can be spread very thickly over such a small quantity of boards.

--

Rick "rickman" Collins

rick.collins@XYarius.com
Ignore the reply address. To email me use the above address with the XY
removed.

Arius - A Signal Processing Solutions Company
Specializing in DSP and FPGA design      URL http://www.arius.com
4 King Ave                               301-682-7772 Voice
Frederick, MD 21701-3110                 301-682-7666 FAX
Reply to
rickman

use for

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I guess

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is quite

volume

packages.

60mhz.

need

periph.

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probably

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though....

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with

to 8

Talk to you local friends about the AT91SAM7A1/A2 chips. ADCs and many timers for PWM-DAC. No significant internal memory though so you need fast SRAM to get the ´high speed.. If that is the problem, then the 60 MIPS 40008 is the way to go.

You can get the AT91RM9200 in TQFP-208 and there is a nice development board from Cogent

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(Many worldwide distributors)

--
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
Reply to
Ulf Samuelsson

for

could

guess

not

quite

volume

packages.

periph.

probably

$5000

with

Oops, sorry about that. I need either fast (5usec max) 4 byte accesses from the external flash or enough internal sram (about 32k x 8) to buffer a block of information which would allow for slower flash access. Ideally I would like to have a small amount of flash (maybe 512K to 1Meg...wow, amazing what is small these days) to hold the main program and some fixed test data and a removable media (compact flash or smart card) of up to xxx megabytes (I guess 64Meg is ok, but its getting where you can't even buy compact flash that small, heh heh). I need to transfer 200K bytes/sec of information from the flash, but it can be in bursts if I have a cache of fast access sram.

I have other projects in mind for the AT91, so this is both an oportunity to learn the chip and its tools without a lot of cash investment. I want to start with a development board, but I will be doing the small run of custom boards.

Thanks,

Rick

Reply to
Rick

You know, the 40008 is starting to look pretty attractive. External DAC gives me the resolution and channels I need anyway, and the smaller 100 pin package will be easier to handle and layout. The on chip sram is fast and is large enough for my needs, and the chip operates twice as fast as the other arm7 flavors.

It looks a bit low on extra general purpose IO pins, but at least for this ap I do not think that is a problem. Software SPI to the DAC should be easy if I choose a serial DAC.

The dev board is cheaper by $50 :-)

Thanks,

Rick

Reply to
Rick

"Rick" skrev i meddelandet news:t8uVb.31549$ snipped-for-privacy@nwrddc01.gnilink.net...

gives

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If you learn how to handle BGA, then the AT91FR40162 is really nice. It is the AT91FR40008 with a 2 MB Flash

--
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
Reply to
Ulf Samuelsson

I saw that part. Very very attractive, but it would be my first time trying to hand solder a BGA, and although I have heard of it being done with a good quality heat gun, it makes me a bit nervous. Plus the pitch is 0.8mm.....

Still, 2MB of internal flash for about a buck or two more than the 40008 part makes me wish I could.

Thanks,

Rick

Reply to
Rick

the

ok,

In that case, take a look at the Philips and OKI ARM MCUs. The Philips parts do not have an external data bus (one will be out later this year), but they have a version that will do most if not all of what you want. The OKI part meets all of your requirements other than the DAC. It comes in a version, the ML67Q5003 which has 512 kB Flash, 32 kB RAM,

4 - 10 bit ADC, 2 PWM outputs, 16550 UART, SIO, 40+ GPIO and hardware SPI and I2C interfaces. Did I miss anything? :)

So an OKI MCU and a DAC SPI or I2C chip should meet all of your requirements, no?

--

Rick "rickman" Collins

rick.collins@XYarius.com
Ignore the reply address. To email me use the above address with the XY
removed.

Arius - A Signal Processing Solutions Company
Specializing in DSP and FPGA design      URL http://www.arius.com
4 King Ave                               301-682-7772 Voice
Frederick, MD 21701-3110                 301-682-7666 FAX
Reply to
rickman

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