"donald" <> wrote in message
news:-...
> Hoi Wong wrote:
>> Thanks for the comments to my post below. It seems like I wasn't clear
>> about the needs for the project when I ask for suggestions on component
>> choice. Instead of continuing the thread below, let me start fresh here.
>>
>> I'm trying to build a portable, low power sound player that plays the
>> selected sound clips from user command. Here are the specs:
>>
>> - Low power
> Are you going to drive a speaker with this device.
> The speaker driver will take more power then the entire cpu, memory, audio
> output circuits.
I do expect driving the loudspeaker to be the major power
drain. At least I wanted the least power consumption when idle.
>> - Small (at the size of a wrist-watch)
> How big are your wrists ?? ;-)
Very very big. Larger than Dave Letterman's hand
>> - Have 8 GIPO (8-pin input)
>> - 8-bit audio
>> - 64~256 short audio clips (2~5 seconds each) at 11kHz
> (back of napkin worst case calulations)
>
> 256 clips * 5 seconds * 11050 (8bit) samples = 14144000 bytes = 14 MBytes
> So a 16 Mbyte flash device would be required.
>
> At the low end:
> 64 clips * 2 seconds * 11050 samples = 1414400 bytes = 1.4 Mbytes
>
> Average:
> 128 clips * 2.5 seconds * 11050 samples = 3535000 bytes = 3.5 Mbytes
>
>> - I have a bunch of free AT49BV162* flash memory to play with
> This chip has 21 address pins and 16 data pins and 6 control pins.
> 43 pins used to interface to your micro.
> I think a serial device would be better.
Thanks for reminding me about the wiring nightmare!
Any suggestion for 16M serial flash memory chips?
>> - I have used Atmel once, but if other options are easier to program,
>> I'll still go with them.
>> - Needs to download the audio clips from USB
> You will never get the size you want with this feature.
You meant it's big because of the footprint of AT90USB* series
or the size of miniUSB port is too big?
>> - Hopefully cheap (I don't need extra features)
> Too build or buy ??
> Is a pcb layout an extra feature ??
I think it's material costs.
Extra feature means many unnecessary GPIO
ports, USART, etc, i.e. PCB layout is not one of the extras
>> Can anybody suggest a simple, easy to interface and program
>> microcontroller
>
> Google "diy mp3"
> Almost every 8 bit micro has been turned into a diy mp3 player.
>
> Lots of hits of what others have done in the past, some are available to
> purchase.
>
> Lots of code out there as well.
>
> Most mp3 decoder chips can play 8 bit samples.
Thanks for the pointer, I found:
http://teuthis.com/html/mmc_mp3.html
and the size of the unit shown on
http://teuthis.com/assets/images/mmc_sm.jpg
fits the size of my giant wrist
But this one gets me thinking about
whether I should go with USB due to
footprint considerations. Maybe I'll
be better off going with miniSD.
However, I'm not sure what are the challenges,
and for power/footprint considerations,
whether I should use raw wave files
of mp3 (that means a decoder).
>> for this project? I'm looking at Atmel's choices, but I'm not sure if I
>> should go for the USB AVRs or ATtiny or Atmega. Ease of design is my
>> first priority, then compactness and cost.
>>
>> I'm especially concerned about how to interface the atmel controllers to
>> AT49BV162* flash memory and how to load the data to it using USB. Should
>> I use GPIO or there are direct memory mapping pins?
>
> USB will be the hardest part of this type of project.
>
> There are two parts to USB. The PC side and the embedded side.
>
> If this is your first project, be sure to have lots of time.
> Some here may be able to do this project within 3 months,
> you may not be so lucky.
From your comments, I guess microSD is the way to go.
For this project, I don't think I need an operating system
on it, but I have no idea how to deal with file systems in
microcontrollers. Can you give me some references to
get started?
> Good luck, let us know how you get along.
>
> donald
Thanks a lot. I'll keep you updated.
Cheers,
Hoi