Microcontrollers for DSP

Hi. What microcontrollers (processors with ROM and RAM and some I/O
onboard so that you can make "devices" from them) are best for DSP?
I've been told of a general purpose processor that I'm told has a RISC
architecture and executes (in general) one instruction per clock cycle
at 32Mhz. Anything better than that which isn't prohibitively expensive
or consumers lots of current?

Cheers,

Ross-c

clemenr@wmin.ac.uk wrote:
> Hi. What microcontrollers (processors with ROM and RAM and some I/O
> onboard so that you can make "devices" from them) are best for DSP?
> I've been told of a general purpose processor that I'm told has a RISC
> architecture and executes (in general) one instruction per clock cycle
> at 32Mhz. Anything better than that which isn't prohibitively expensive
> or consumers lots of current?
> 
> Cheers,
> 
> Ross-c
> 
How long is a piece of string?

How cheap are you expecting? Controller oriented DSPs, like the TI C2000 
family, the Freescale 56F800, and the Microchip DSPic are cheap. Some of 
the TI devices can run up to a couple of hundred megs, too.

Without a clearer idea of what you are trying to achieve its hard to say 
much more.

Regards,
Steve

Hello Ross,

As Steve said that's hard to say with more info about what you want to 
do. For example, will your algorithm require lots of multiplications? 
Need more than a few k or RAM?

I am currently in the same pit. There are cheap DSP but only with 
mediocre on-chip ADC capabilities and many of them eat batteries as if 
it was popcorn. Look at the TI MSP430 series. 16 bit engine and the 
luxury versions have an on-chip HW multiplier. But don't expect tens of 
MHz here.

Regards, Joerg

http://www.analogconsultants.com

Hi. I would like to know what sorts of microcontrollers are available
so that I could design some "student projects" with DSP chips. So, the
applications would be limited by the performance of what we can afford
more than vice-versa. Basically, if we had something that could sample
audio and play it back, then that would make a lot of interesting
things possible.

The microcontrollers used in student projects at the moment are
generally in the 4-5 pound range. I.e. next to nothing. Certainly at
40-50 pounds each and no more than say 10 pounds for discrete
components we're still in the price range of a typical student project.
Bits and pieces such as raw materials etc are available off the shelf
here, and hence aren't as expensive here as they would be otherwise.

Cheers,

Ross-c

Hello Ross,

> Hi. I would like to know what sorts of microcontrollers are available
> so that I could design some "student projects" with DSP chips. ...

uC or DSP? Very different beasts.

You'll have to invest the time and trudge through the mfg sites. TI, 
Microchip, Atmel, Analog Devices etc. There is usually a budgetary price 
listed. When you have picked one out go to Digikey and see what it costs 
in low quantities. In the UK Farnell might be easier.

If you can live with 12bit audio there is plenty. In the DSP arena for 
example the TMS320LF2401. Mostly you'd have to supply your own DAC though.

If you need very low quantities do the search the other way around. Look 
what you local hobby shops have and then delve into the data sheets to 
see what fits the bill. Get something on a header board to save you the 
really fine pitch solder job. If you don't want to solder much at all 
look for a low cost evaluation board, often available from manufacturers 
like TI and usually including the software suite.

Regards, Joerg

http://www.analogconsultants.com

<clemenr@wmin.ac.uk> wrote in message
news:1131129152.583927.3770@z14g2000cwz.googlegroups.com...
> Hi. What microcontrollers (processors with ROM and RAM and some I/O
> onboard so that you can make "devices" from them) are best for DSP?
> I've been told of a general purpose processor that I'm told has a RISC
> architecture and executes (in general) one instruction per clock cycle
> at 32Mhz. Anything better than that which isn't prohibitively expensive
> or consumers lots of current?
>
> Cheers,
>
> Ross-c
>
Try the TI C6711 DSK.It's used in most Unis.

McC

Thanks for all the info.

What we're planning to do is pre-design a few simple "computer boards"
that students can use for projects. E.g. the first one we plan to do is
a real basic microcontroller board with just the processor and a serial
interface. That could be used for basic MIDI projects where there is no
need for a LCD and buttons. Another would be the same but have a LCD
and buttons. I have a colleague (I'm not sure what his exact title is)
who is quite enthusiastic about building things, and says that if I
give basic specifications for boards, that he'll design the full
circuit, build the PCB, etc. He did the same for much more fuller
featured microcontroller boards in use now, and certainly does a very
professional job. Then if students want to undertake projects on MIDI
controllers (I have one such student already) we can give them a PCB
and parts list, or build the thing for them which will get them started
much quicker. I'm asking about DSP processors not because I have direct
experience of them, but because having two basic DSP boards ready would
expand the number of potential projects considerably.

I should point out that I do not teach DSP. The degree I'm most
associated with is a degree in "Music Innovation". The students haven't
been given the background to do real DSP programming, but are taught
(at least those who take my "Audio Application Development" module) to
write music synthesis software using a library. (Currently Java/JSyn).
If we had the basic DSP boards around, then I think it would be a valid
project for the students to implement a "synthesiser module" using
either a library, or cobbling together routines from the music dsp list
library. [note: of course including detailed information about the
source of the code snippets used in their writeup and code comments].

I'll look into the chips recommended here. 12 bits is a bit
restrictive, but OK for a "prototype".

I must point out that I'm only "thinking about things now". I can't
guarantee what I might actually do or not do, or when things might
happen. I've recently moved from a Computer Science School to an
Engineering School and am still a bit "kid in the candy shop" now I've
realised what the infrastructure here means that I can do that I
couldn't do before.

By the way, do any of the DSP boards come with C++ compilers rather
than C so that it would be feasible to port Stk?

Cheers,

Ross-c

clemenr@wmin.ac.uk wrote:
> Thanks for all the info.
> 
> What we're planning to do is pre-design a few simple "computer boards"
> that students can use for projects. E.g. the first one we plan to do is
> a real basic microcontroller board with just the processor and a serial
> interface. That could be used for basic MIDI projects where there is no
> need for a LCD and buttons. Another would be the same but have a LCD
> and buttons. I have a colleague (I'm not sure what his exact title is)
> who is quite enthusiastic about building things, and says that if I
> give basic specifications for boards, that he'll design the full
> circuit, build the PCB, etc. He did the same for much more fuller
> featured microcontroller boards in use now, and certainly does a very
> professional job. Then if students want to undertake projects on MIDI
> controllers (I have one such student already) we can give them a PCB
> and parts list, or build the thing for them which will get them started
> much quicker. I'm asking about DSP processors not because I have direct
> experience of them, but because having two basic DSP boards ready would
> expand the number of potential projects considerably.
> 
> I should point out that I do not teach DSP. The degree I'm most
> associated with is a degree in "Music Innovation". The students haven't
> been given the background to do real DSP programming, but are taught
> (at least those who take my "Audio Application Development" module) to
> write music synthesis software using a library. (Currently Java/JSyn).
> If we had the basic DSP boards around, then I think it would be a valid
> project for the students to implement a "synthesiser module" using
> either a library, or cobbling together routines from the music dsp list
> library. [note: of course including detailed information about the
> source of the code snippets used in their writeup and code comments].
> 
> I'll look into the chips recommended here. 12 bits is a bit
> restrictive, but OK for a "prototype".
> 
> I must point out that I'm only "thinking about things now". I can't
> guarantee what I might actually do or not do, or when things might
> happen. I've recently moved from a Computer Science School to an
> Engineering School and am still a bit "kid in the candy shop" now I've
> realised what the infrastructure here means that I can do that I
> couldn't do before.
> 
> By the way, do any of the DSP boards come with C++ compilers rather
> than C so that it would be feasible to port Stk?
> 
> Cheers,
> 
> Ross-c

Once you add in the cost of a suitable LCD panel and buttons then the 
basic cost of the DSP will become much less significant.

However obviously you want something more simple to assemble etc also 
and so any complex pinned parts are out of the question.  I'd probably 
go for something like the MSP430, if you feel soldering and layout 
skills are adept enough then even something like the Analog Devices 
ADSP-21xx series.

Quite alot is possible using just a basic PC.  Especially if you're 
running an operating system that allows access a bit closer to hardware, 
such as linux.  That might be a good platform to start with.

<clemenr@wmin.ac.uk> wrote in message 
news:1131135152.068666.77880@g14g2000cwa.googlegroups.com...
> Hi. I would like to know what sorts of microcontrollers are available
> so that I could design some "student projects" with DSP chips. So, the
> applications would be limited by the performance of what we can afford
> more than vice-versa. Basically, if we had something that could sample
> audio and play it back, then that would make a lot of interesting
> things possible.
>
> The microcontrollers used in student projects at the moment are
> generally in the 4-5 pound range. I.e. next to nothing. Certainly at
> 40-50 pounds each and no more than say 10 pounds for discrete
> components we're still in the price range of a typical student project.
> Bits and pieces such as raw materials etc are available off the shelf
> here, and hence aren't as expensive here as they would be otherwise.
>
> Cheers,
>
> Ross-c

About the cheapest for a dsp board.
The freescal(moto) MC56F8300DSK
costs US$79 from digikey
<http://www.digikey.com/scripts/DkSearch/dksus.dll?Criteria?Ref=416899&Site=US&Cat=33424044>
comes with 56f8323 + efield sensor + audio

Xilinx spartan3 fpga starter kit - can do a bit of dsp with that
but would be a bit more of a learning curve.
US$99  currently has spartan3 starter kit + cpld starter kit
<http://www.xilinx.com/xlnx/xebiz/designResources/ip_product_details.jsp?key=HW-SPAR3-CPLD-DK>

To have a play without having to buy anything
have a look on techonline.com for their virtual labs especially
the uclinux blackfin board. Just need a decent speed net connection.
http://www.techonline.com/community/prod_eval/devel_systems
http://www.techonline.com/community/prod_eval/devel_systems/37200
http://seminar2.techonline.com/s/analogdevices_sep3004   webcast

They also have a 56800 board
http://www.techonline.com/community/prod_eval/devel_systems/37300

To buy one of the blackfin stamp boards is approx US$170.
Nice boards, I just brought myself one.
http://www.analog.com/en/prod/0%2C2877%2CBF533%25252DSTAMP%2C00.html
http://blackfin.uclinux.org/
http://docs.blackfin.uclinux.org/doku.php?id=buy_stuff
http://www.analog.com/en/prod/0%2C2877%2CBF537%25252DSTAMP%2C00.html

Apparently the Danville boards are still available at US$199 from Arrow
http://www.altera.com/products/devkits/partners/kit-adi-adds.html

Unless you want to build your own board
maybe worth looking at microcontrollers
like the arm7 chips from a few manufacturers.
www.sparkfun.com sell boards from www.olimex.com
that use chips from Philips(lpc2xxx) , ST , Analog etc

Alex 

On Fri, 04 Nov 2005 21:07:52 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

>Hello Ross,
>
>> Hi. I would like to know what sorts of microcontrollers are available
>> so that I could design some "student projects" with DSP chips. ...
>
>uC or DSP? Very different beasts.

   Well, yes, sort of. There's a bit of overlap, though it appears the
OP doesn't see the distinction between a microcontroller and a DSP.
   There are lots of microcontrollers with traditional microprocessor
cores. These run quite slow for DSP tasks, as they have to go through
a lot of operations to do a typical DSP calculation.
   There are a few microcontrollers with MAC devices stuck onto them,
such as the DSPic and the higher-end MSP430, which makes them
substantially faster for DSP tasks, but it may still takes several
cycles to load/read the MAC unit.
   Most (all?) low-end DSP nowadays ARE microcontrollers with a
"traditional" DSP for the processor core, and usually do single-cycle
instruction execution, including MAC's, thus they are several times
faster than the "microcontroller-with-MAC".

>
>You'll have to invest the time and trudge through the mfg sites. TI, 
>Microchip, Atmel, Analog Devices etc. There is usually a budgetary price 
>listed. When you have picked one out go to Digikey and see what it costs 
>in low quantities. In the UK Farnell might be easier.
>
>If you can live with 12bit audio there is plenty. In the DSP arena for 
>example the TMS320LF2401. Mostly you'd have to supply your own DAC though.
>
>If you need very low quantities do the search the other way around. Look 
>what you local hobby shops have and then delve into the data sheets to 
>see what fits the bill. Get something on a header board to save you the 
>really fine pitch solder job. If you don't want to solder much at all 
>look for a low cost evaluation board, often available from manufacturers 
>like TI and usually including the software suite.
>
>Regards, Joerg
>
>http://www.analogconsultants.com