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arm7 core with fast monolithic 12-bit ADC

 
 
Jon Kirwan
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      02-11-2009, 10:10 PM
I'm just getting into a project which "prefers" the ARM7 for business
reasons, not technical ones. I do _not_ have experience writing for
the ARM7 beyond some modest playing around, but will muddle through
that part when the time comes.

I'm looking for an ARM7TDMI core (or upward compatible) that includes
a monolithic (unless someone goes through all the trouble of
wire-bonding in packaging for reasonable prices) 12-bit minimum width,
1.5MHz minimum rate ADC (10.5-bit or so realizable at 2MHz with 1-2V
signals is fine.) Pipelined sampling and conversion stages is okay to
get the speed, as only one signal needs to be measured. Flash
programming of code, 1000-5000 pc qtys. Other features are far less
important, but RAM should be at least 2k (4k would be safer) and flash
should be at least 32k-64k (128k would probably be massive overkill.)
I/O required is probably less then 20 I/O pins (12, I'm counting right
now, outside the ADC input.) So a 44-pin package is well more than I
need.

There is a core algorithm involved that processes the data, but to be
honest I don't need a blazingly fast cpu here -- the core parts that
require very fast speed will be written in assembly. I won't be using
floating point, except for a few custom routines I'll write. A fully
combinatorial barrel shifter with the ability to find the leading bit
and record the number of shifts required is a plus, though. I already
know that division is an issue for the ARM7 (software), but that is
okay as I keep division to a minimum, using wider 'registers' and
multiplicative sums and tracking divisors, holding the division parts
till the very end.

I've seen a few cases with fancy debug trace buffers available over
JTAG and that would be "high cotton" if I could find that, together
with the ADC. But it really isn't necessary.

The main thing I'm looking for a fast, decent 12-bit or better ADC
inside an ARM7TDMI (or upward compatible) cpu. The 1.5MHz minimum
requirement is a bit of a stretch, perhaps. But it is important and
I'm currently using an external ADC for this (which easily reach much
higher than this and with decent bits.) Pushing towards 2-3MHz would
be pure ecstasy.

Right now I'm just trying to compile a list for examination. So even
things that are close (1MHz, for example) would be okay to include.
I'll talk it over, later, to see what we may have to accept.

The other option is to use a non-ARM7TDMI compatible cpu, if that is
the only way to get there (for example, Atmel's XMEGA.) I'm hoping
there are some options in the ARM7 field, though.

Thanks very much in advance for any suggestions to add to the list.

Jon
 
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Wilco Dijkstra
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      02-11-2009, 10:32 PM

"Jon Kirwan" <(E-Mail Removed)> wrote in message news(E-Mail Removed)...

> There is a core algorithm involved that processes the data, but to be
> honest I don't need a blazingly fast cpu here -- the core parts that
> require very fast speed will be written in assembly. I won't be using
> floating point, except for a few custom routines I'll write. A fully
> combinatorial barrel shifter with the ability to find the leading bit
> and record the number of shifts required is a plus, though. I already
> know that division is an issue for the ARM7 (software), but that is
> okay as I keep division to a minimum, using wider 'registers' and
> multiplicative sums and tracking divisors, holding the division parts
> till the very end.


If clz and division are important then you might want to consider Cortex-M3
instead, for example the LM3S628 (8x 1MHz adc, 50MHz, 32KB flash,
8KB SRAM, 48 LQFP).

Wilco


 
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-jg
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      02-11-2009, 11:59 PM
Jon Kirwan wrote:

> I'm just getting into a project which "prefers" the ARM7 for business
> reasons, not technical ones. I do _not_ have experience writing for
> the ARM7 beyond some modest playing around, but will muddle through
> that part when the time comes.
>
> I'm looking for an ARM7TDMI core (or upward compatible) that includes
> a monolithic (unless someone goes through all the trouble of
> wire-bonding in packaging for reasonable prices) 12-bit minimum width,
> 1.5MHz minimum rate ADC (10.5-bit or so realizable at 2MHz with 1-2V
> signals is fine.)
> Right now I'm just trying to compile a list for examination. So even
> things that are close (1MHz, for example) would be okay to include.
> I'll talk it over, later, to see what we may have to accept.


12 bits and Multi MHz is a stretch,
Analog devices have 12 bits and 1MHz, in ARM7.

NXP have Cortex cores at 1MHz / 12 bits, and Atmel AT91SAM3
seems to have slipped - I think that was 12 bits/ 1MSPS too
..
Documents suggesting Q3/Q4 08 SAM3 samples, have not been correct,
and their newest ARM family guide, skips the SAM3 entirely

> The other option is to use a non-ARM7TDMI compatible cpu, if that is
> the only way to get there (for example, Atmel's XMEGA.) I'm hoping
> there are some options in the ARM7 field, though.


XMega is a little short on ADC speed ?.

>
> Thanks very much in advance for any suggestions to add to the list.


If you already have an ADC chip, why not morph slightly, and
make that a TI Picolo : $3 for 12 bit ADC 325ns conversion, high
precision
timers, (and a free DSP), and then any-old-arm can do the rest. ?

-jg
 
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Jon Kirwan
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      02-12-2009, 04:09 AM
On Wed, 11 Feb 2009 22:32:36 -0000, "Wilco Dijkstra"
<(E-Mail Removed)> wrote:

>"Jon Kirwan" <(E-Mail Removed)> wrote in message news(E-Mail Removed)...
>
>> There is a core algorithm involved that processes the data, but to be
>> honest I don't need a blazingly fast cpu here -- the core parts that
>> require very fast speed will be written in assembly. I won't be using
>> floating point, except for a few custom routines I'll write. A fully
>> combinatorial barrel shifter with the ability to find the leading bit
>> and record the number of shifts required is a plus, though. I already
>> know that division is an issue for the ARM7 (software), but that is
>> okay as I keep division to a minimum, using wider 'registers' and
>> multiplicative sums and tracking divisors, holding the division parts
>> till the very end.

>
>If clz and division are important then you might want to consider Cortex-M3
>instead, for example the LM3S628 (8x 1MHz adc, 50MHz, 32KB flash,
>8KB SRAM, 48 LQFP).


Actually, division is less important. I've got those operations down
to a bare minimum and can tolerate some execution time. I'm still
hoping for something more than 1MHz on a monolithic ADC, which will
put a small kink into the idea of moving away from an outboard ADC.
I'm a bit unhappy at 1Mhz. It might be livable, but the extra bit of
speed would be worth going after. If you don't know of one, then I
guess there may be nothing staring me in the face that I've missed on
a quick search this morning. But don't get me wrong. I'm not opposed
to an M3. I'm just waffling about the ADC speed.

Jon
 
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Jon Kirwan
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      02-12-2009, 04:26 AM
On Wed, 11 Feb 2009 15:59:53 -0800 (PST), -jg
<(E-Mail Removed)> wrote:

>Jon Kirwan wrote:
>
>> I'm just getting into a project which "prefers" the ARM7 for business
>> reasons, not technical ones. I do _not_ have experience writing for
>> the ARM7 beyond some modest playing around, but will muddle through
>> that part when the time comes.
>>
>> I'm looking for an ARM7TDMI core (or upward compatible) that includes
>> a monolithic (unless someone goes through all the trouble of
>> wire-bonding in packaging for reasonable prices) 12-bit minimum width,
>> 1.5MHz minimum rate ADC (10.5-bit or so realizable at 2MHz with 1-2V
>> signals is fine.)
>> Right now I'm just trying to compile a list for examination. So even
>> things that are close (1MHz, for example) would be okay to include.
>> I'll talk it over, later, to see what we may have to accept.

>
>12 bits and Multi MHz is a stretch,


Yes, I'm kind of thinking so, too.

>Analog devices have 12 bits and 1MHz, in ARM7.


Yes, I had only this morning before posting noted the ADuC7022 from
Analog.

>NXP have Cortex cores at 1MHz / 12 bits, and Atmel AT91SAM3
>seems to have slipped - I think that was 12 bits/ 1MSPS too
>.


I think I saw an LPC175x series with 12-bit. But no information on
when it will be sampling. Apparently, not now anyway. On the XMEGA
with 2MHz 12-bit pipelined ADC, Digikey told me yesterday that it was
at least sometime April before they'd see any there to ship. Maybe
longer. Which just may... may... be okay.

>Documents suggesting Q3/Q4 08 SAM3 samples, have not been correct,
>and their newest ARM family guide, skips the SAM3 entirely


Thanks.

>> The other option is to use a non-ARM7TDMI compatible cpu, if that is
>> the only way to get there (for example, Atmel's XMEGA.) I'm hoping
>> there are some options in the ARM7 field, though.

>
>XMega is a little short on ADC speed ?.


Well, supposedly I saw an ATxmega16A4 (up to 128A4) variety with 2MHz
and 12bit, nicely pipelined for my needs. So in one-off conversions,
it is too slow. But free-running it looks good and would suit the
application (well, I haven't checked through the specifications in any
detail, so there might be something there that would kill the idea.)

>> Thanks very much in advance for any suggestions to add to the list.

>
>If you already have an ADC chip, why not morph slightly, and
>make that a TI Picolo : $3 for 12 bit ADC 325ns conversion, high
>precision
>timers, (and a free DSP), and then any-old-arm can do the rest. ?


I hadn't even thought to look at that one. It kind of defeats the
idea using two big chips -- I'm looking to reduce the chip and
supplier count, not increase it. But if there is, say, 12-14 I/Os
there and if I can set up RS232 on it then I might not need anything
else. The 64kb flash and 12kb ram seems okay. This application used
to run on an ADSP21xx, so I'm perfectly comfortable with DSPs for
this. I just didn't like my earlier experiences with the TI C30/C40
clan. If this is another roll of one of those cores, I'm not going to
be happy unless they've learned a lot more about their own chips,
enough that they can explain an observed cycle count running out of
cache. They couldn't tell me why a 7 cycle count loop in cache took
11 cycles, years back. We spent weeks on the phone with their
technical folks pouring carefully over various ways of forced
interlock waits and never got anywhere.

Thanks for the thought. I'll take a closer look.

Jon
 
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Jon Kirwan
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Posts: n/a
 
      02-12-2009, 05:40 AM
On Wed, 11 Feb 2009 15:59:53 -0800 (PST), -jg
<(E-Mail Removed)> wrote:

><snip>
>TI Picolo : $3 for 12 bit ADC 325ns conversion
><snip>


I'm seeing towards $4. But then I won't really know until an order is
placed. Can you say anything about the tool chains you've experienced
for this device? Cost, support reponsiveness, etc. Alternative
development tools you looked at but didn't actually wind up trying
out?

Jon
 
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-jg
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      02-12-2009, 07:20 AM
>
> I'm seeing towards $4. *But then I won't really know until an order is
> placed. *Can you say anything about the tool chains you've experienced
> for this device? *Cost, support reponsiveness, etc. *Alternative
> development tools you looked at but didn't actually wind up trying
> out?


Not on this family yet, but I did like the look of the Peripheral mix,
so it is on our radar for future use...
..
Very fast ADC, and high resolution timers.

TI are pushing some low-cost stuff
Experimenter Kit w/ControlCARD I see in stock at Newark for ~$82,
Piccolo controlSTICK is a USB stick, for $40.50

so that would be an easy way to quickly try the latest tools ?.

-jg

 
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Jon Kirwan
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      02-12-2009, 08:46 AM
On Wed, 11 Feb 2009 23:20:12 -0800 (PST), -jg
<(E-Mail Removed)> wrote:

>> I'm seeing towards $4. *But then I won't really know until an order is
>> placed. *Can you say anything about the tool chains you've experienced
>> for this device? *Cost, support reponsiveness, etc. *Alternative
>> development tools you looked at but didn't actually wind up trying
>> out?

>
>Not on this family yet, but I did like the look of the Peripheral mix,
>so it is on our radar for future use...
>.
>Very fast ADC, and high resolution timers.


Yeah. I'm impressed.

>TI are pushing some low-cost stuff
>Experimenter Kit w/ControlCARD I see in stock at Newark for ~$82,
>Piccolo controlSTICK is a USB stick, for $40.50
>
>so that would be an easy way to quickly try the latest tools ?.


I suppose so. I'm a little disappointed looking at Eclipse
development tool costs for active development (not trial stuff.)
That's kind of off my radar range, if I decide to go that way. Which
means I need to dig a little deeper about tools. But yes, the device
appears attractive to me and I definitely appreciate the pointer. I
think I'd heard the name dropped here once or twice, but never took
notice before. But my head is turned now. So I'll put a little
effort into looking further.

Jon
 
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arzo
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Posts: n/a
 
      02-12-2009, 09:01 AM
On Feb 12, 3:10*am, Jon Kirwan <(E-Mail Removed)> wrote:
> I'm just getting into a project which "prefers" the ARM7 for business
> reasons, not technical ones. *I do _not_ have experience writing for
> the ARM7 beyond some modest playing around, but will muddle through
> that part when the time comes.
>
> I'm looking for an ARM7TDMI core (or upward compatible) that includes
> a monolithic (unless someone goes through all the trouble of
> wire-bonding in packaging for reasonable prices) 12-bit minimum width,
> 1.5MHz minimum rate ADC (10.5-bit or so realizable at 2MHz with 1-2V
> signals is fine.) *Pipelined sampling and conversion stages is okay to
> get the speed, as only one signal needs to be measured. *Flash
> programming of code, 1000-5000 pc qtys. *Other features are far less
> important, but RAM should be at least 2k (4k would be safer) and flash
> should be at least 32k-64k (128k would probably be massive overkill.)
> I/O required is probably less then 20 I/O pins (12, I'm counting right
> now, outside the ADC input.) *So a 44-pin package is well more than I
> need.
>
> There is a core algorithm involved that processes the data, but to be
> honest I don't need a blazingly fast cpu here -- the core parts that
> require very fast speed will be written in assembly. *I won't be using
> floating point, except for a few custom routines I'll write. *A fully
> combinatorial barrel shifter with the ability to find the leading bit
> and record the number of shifts required is a plus, though. *I already
> know that division is an issue for the ARM7 (software), but that is
> okay as I keep division to a minimum, using wider 'registers' and
> multiplicative sums and tracking divisors, holding the division parts
> till the very end.
>
> I've seen a few cases with fancy debug trace buffers available over
> JTAG and that would be "high cotton" if I could find that, together
> with the ADC. *But it really isn't necessary.
>
> The main thing I'm looking for a fast, decent 12-bit or better ADC
> inside an ARM7TDMI (or upward compatible) cpu. *The 1.5MHz minimum
> requirement is a bit of a stretch, perhaps. *But it is important and
> I'm currently using an external ADC for this (which easily reach much
> higher than this and with decent bits.) *Pushing towards 2-3MHz would
> be pure ecstasy.
>
> Right now I'm just trying to compile a list for examination. *So even
> things that are close (1MHz, for example) would be okay to include.
> I'll talk it over, later, to see what we may have to accept.
>
> The other option is to use a non-ARM7TDMI compatible cpu, if that is
> the only way to get there (for example, Atmel's XMEGA.) *I'm hoping
> there are some options in the ARM7 field, though.
>
> Thanks very much in advance for any suggestions to add to the list.
>
> Jon


these website i found on net are very informative.
plz check all the links and enjoy your self.

http://picinf.blogspot.com/ http://microcontroller51.blogspot.com/
http://makeonlinemoneyinf.blogspot.com/
regardz
 
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arzo
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Posts: n/a
 
      02-12-2009, 09:01 AM
On Feb 12, 3:10*am, Jon Kirwan <(E-Mail Removed)> wrote:
> I'm just getting into a project which "prefers" the ARM7 for business
> reasons, not technical ones. *I do _not_ have experience writing for
> the ARM7 beyond some modest playing around, but will muddle through
> that part when the time comes.
>
> I'm looking for an ARM7TDMI core (or upward compatible) that includes
> a monolithic (unless someone goes through all the trouble of
> wire-bonding in packaging for reasonable prices) 12-bit minimum width,
> 1.5MHz minimum rate ADC (10.5-bit or so realizable at 2MHz with 1-2V
> signals is fine.) *Pipelined sampling and conversion stages is okay to
> get the speed, as only one signal needs to be measured. *Flash
> programming of code, 1000-5000 pc qtys. *Other features are far less
> important, but RAM should be at least 2k (4k would be safer) and flash
> should be at least 32k-64k (128k would probably be massive overkill.)
> I/O required is probably less then 20 I/O pins (12, I'm counting right
> now, outside the ADC input.) *So a 44-pin package is well more than I
> need.
>
> There is a core algorithm involved that processes the data, but to be
> honest I don't need a blazingly fast cpu here -- the core parts that
> require very fast speed will be written in assembly. *I won't be using
> floating point, except for a few custom routines I'll write. *A fully
> combinatorial barrel shifter with the ability to find the leading bit
> and record the number of shifts required is a plus, though. *I already
> know that division is an issue for the ARM7 (software), but that is
> okay as I keep division to a minimum, using wider 'registers' and
> multiplicative sums and tracking divisors, holding the division parts
> till the very end.
>
> I've seen a few cases with fancy debug trace buffers available over
> JTAG and that would be "high cotton" if I could find that, together
> with the ADC. *But it really isn't necessary.
>
> The main thing I'm looking for a fast, decent 12-bit or better ADC
> inside an ARM7TDMI (or upward compatible) cpu. *The 1.5MHz minimum
> requirement is a bit of a stretch, perhaps. *But it is important and
> I'm currently using an external ADC for this (which easily reach much
> higher than this and with decent bits.) *Pushing towards 2-3MHz would
> be pure ecstasy.
>
> Right now I'm just trying to compile a list for examination. *So even
> things that are close (1MHz, for example) would be okay to include.
> I'll talk it over, later, to see what we may have to accept.
>
> The other option is to use a non-ARM7TDMI compatible cpu, if that is
> the only way to get there (for example, Atmel's XMEGA.) *I'm hoping
> there are some options in the ARM7 field, though.
>
> Thanks very much in advance for any suggestions to add to the list.
>
> Jon

these website i found on net are very informative.
plz check all the links and enjoy your self.

http://picinf.blogspot.com/ http://microcontroller51.blogspot.com/
http://makeonlinemoneyinf.blogspot.com/
regardz
 
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