Wave Audio Recorder with XMega128A1 and SD-Card

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#1
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Hello there,

I just finished the prototype of a standalone audio recorder, that captures 16Bit / 48kHz stereo on a SD-Card. I needed this device for outside recordings and it was a nice project to learn more about the XMega controllers. So here it is:

http://www.electricstart.de/elec...

Features:
Main controller: ATXMEGA128A1 (ES)
Sub controllers: ATTiny2313 x2
Display: Graphic LCD with BG-lighting, 132x32px.
A/D: Cirrus CS5343
D/A: Cirrus CS4344
I2S->SPDIF: Cirrus CS8406
Headphone Amp: DA1308A
Buffer SRAM: CY7C1019 / 128kByte
Step-Up Converter: LM2621
Running on 2 AA-Cells
Supports SD-Cards up to 2GB / 176 mins of music
Recording format: Raw-PCM, no FAT

Input: 1x Line analog
Outputs: 1x Line analog
1x Headphone
1x SPDIF optical

The device is running like a tape recorder. It plays and records instantly from the current position on the card. You can also do fast forward and fast rewind, skip to beginning of the card or the last stop sector. Some features are not implemented yet and are subject to my desires or ideas that will come up. The prototype is working well for now, you can find some performance plots in the compressed file above. Questions and suggestions are welcome :wink:

Greetings and Regards,
TravelRec.

Attachment(s): 

Last Edited: Tue. Nov 18, 2008 - 04:01 PM
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Cool.

Does it write MP3's to that SD card, or just use it to store your own format?

274,207,281-1 The largest known Mersenne Prime

Measure twice, cry, go back to the hardware store

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Truly awesome.

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Torby wrote:
Cool.

Does it write MP3's to that SD card, or just use it to store your own format?

No, not MP3. It stores and reads raw pcm, so wave format @ 48kHz and 16 bits resolution. It was the intention to have a device that can handle uncompressed audio to get a high signal quality. It´s comparable with DAT recorder signal quality.

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Way cool.

I was just wondering about writing to the flash card so a PC could read.

274,207,281-1 The largest known Mersenne Prime

Measure twice, cry, go back to the hardware store

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The data is written as a stream to the card and is also read as a stream. To transfer the data to a computer, I use freeware that can read the sectors sequentially without any FAT format. Link to the freeware: http://mh-nexus.de/de/hxd/
After writing the sectors with the software into a file, I can import it directly to a wave editor e.g. WaveLab or a sequencer e.g. Cubase or similar.

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The link is dead and I can't find the project on your website.

Rick

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RickB wrote:
The link is dead and I can't find the project on your website.

Rick

Oh sorry, the link was wrong, is corrected now. Hmm - nobody has seen it before :roll:

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Now that's a utility I could have lots of uses for!

274,207,281-1 The largest known Mersenne Prime

Measure twice, cry, go back to the hardware store

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Are you planning to build one for yourself?

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Thanks for the project, it was looking for a good exaple to start with XMEGA.
I'm new with XMEGA and some good example is always welcome. :)
Davide

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sorry a short notice: in the last message I want to say: "I was looking for" and not "it was"..
:)
Davide

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This project kicks butts... Awesome. And I like the details like the backlight control (LDR). You did a real great job here! So I assume the ADC of the Atmel wasn't sufficient?! ;)

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No, the internal ADCs are good for measuring different analogue signals, but for audio in studio quality 12bits and the THD and S/N-ratio characteristics are not good enough. Everything below 16 bits / 48kHz (with <80db dynamic range) is not sufficient, if you want to process the audio signal any further. Since most PC/MAC wave editors support the raw audio format, this was my first choice without having to handle with file systems.

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A little video that shows some of the current functions: http://www.youtube.com/watch?v=F...

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I was just wondering about writing to the flash card so a PC could read.

simulation emprunt immobilier

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The data written on the card is plain RAW PCM (little endian, 2s complement format), so a Disk monitor can read the sectors and write them into a file, that is directly .WAV 48/16 compatible.

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There seems to be a problem with the current rar file as I am unable to extract it. Could you please check the file when you have a chance?

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For me it´s okay - sorry for being late...

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Is there any chance you could post some of your code? I'm interested in the read/write memory function you used. Thanks.