Forums

at91 choices for my application...help

Started by Rick February 8, 2004
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


Rick wrote:
> 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? >
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

Rick wrote:
> 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.
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: http://www.semiconductors.philips.com/pip/LPC2124FBD64.html 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
Leon Heller <aqzf13@dsl.pipex.com> writes:

> Availability seems to be a problem at the moment, but that should improve.
I think I have heard this before... :) - Ville -- Ville Voipio, Dr.Tech., M.Sc. (EE)
Rick wrote:
> > 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?
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

"Tauno Voipio" <tauno.voipio@iki.fi.NOSPAM.invalid> skrev i meddelandet
news:6CnVb.66$is1.41@read3.inet.fi...
> Rick wrote: > > 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? > > >
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 &#2013266100;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 www.cogcomp.com (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
"rickman" <spamgoeshere4@yahoo.com> wrote in message
news:40263A5E.B54C8DA9@yahoo.com...
> Rick wrote: > > > > 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? > > 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. > > -- >
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
<snip>

> 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 >
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

"Rick" <rick@skyko.com> skrev i meddelandet
news:t8uVb.31549$EH5.12884@nwrddc01.gnilink.net...
> <snip> > > > 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 > > > > 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, >
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
<snip>
> > If you learn how to handle BGA, then the AT91FR40162 is really nice. > It is the AT91FR40008 with a 2 MB Flash
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