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Author Topic: SIngle CHIP Sd-MMC player  (Read 3971 times)
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murugan
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« on: May 21, 2011, 08:38:57 08:38 »

hi every one
want a project using avr and sd-mmc please visit following website or download attachment
http://elm-chan.org/he_a_e.html


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DarkClover
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« Reply #1 on: July 14, 2011, 09:47:55 21:47 »

Well, as long as the files on the SD-Card are in raw format there are just
minor problems.

According to the schematics you posted, the data would be MIDI or something
similar to this.
If you want to play raw music files (like raw encoded WAV) you need a DAC before
the speakers or simulate the soundwaves using PWM (the capacitors filter the HF-parts)
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rtm
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« Reply #2 on: July 23, 2011, 06:49:42 06:49 »

DarkClover,

here is the trick: this player with 8-pins chip is palying raw WAV by using PWM. Attiny85 has 2-channel high speed PWM, so it is very sutable for this, as it does not need output low band filter after high speed PWM.
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DarkClover
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« Reply #3 on: July 23, 2011, 12:33:14 12:33 »

DarkClover,

here is the trick: this player with 8-pins chip is palying raw WAV by using PWM. Attiny85 has 2-channel high speed PWM, so it is very sutable for this, as it does not need output low band filter after high speed PWM.

Thats very nice! I thought about that in my post Smiley

Well, does the ATtiny85 emulate some filesystem for the SD card or
just read the data blocks from it ?
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rtm
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« Reply #4 on: July 23, 2011, 06:33:08 18:33 »

DarkClover,

the author of this toy is a conjurer: he has made a special module for small microcontrollers that uses only few dozens bytes of memory - Petit FatFs. It is working with true FAT on the card with only a few small restrictions in writting.
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DarkClover
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« Reply #5 on: August 01, 2011, 10:07:43 22:07 »

Thanks for the hint rtm!
I know elm since I started with programming microcontroller but I didn't notice that he
had designed such a small FS.

I really can use that kind of stuff for my new picture badge project. Since it's quite fast
I can even display some videos or animations. And because it's so small I have enough
space for transitions or blending Smiley
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DarkClover
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« Reply #6 on: September 18, 2011, 09:32:25 21:32 »

Update...
It really was a success. My badge can even display some small animated pictures now. When my prototype and it's code is finished I'll put all the data up here. Thanks anyway.
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