Hacking into "Thumb" MP3 players

For the few dollars they cost, you get an awful lot of clever electronics in those little thumb USB MP3 players.. a little TOO clever for my application. I want to use one to play a sound effect when triggered..once only per triggering. However armed with only one button which, in various guises, turns it on, plays it (endlessly), pauses it or turns it off, this is proving to be a mission that even a PIC cannot resolve. The wretched thing seems to even sense if there is 1.5v going up the USB (in which case if boosts it up to 3.3v and acts like a player) or 5 volts (in which case it acts like a flash drive). Anyone ever seen a schematic for one of these Chinese widgets (full of unidentifiable chips) ? M

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moby
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A month or so ago, I posted a brief description of the circuit in a Philips-Nike unit. There's really only one chip (plus two Toshiba memory chips). The rest is all discretes (about 150 of them).

I'll just quote it again below:

----- I just looked, the Nike/Philips unit uses a Sigmatel 3410L SOC which has the DC-DC converter logic on chip (along with the 65MHz DSP, USB interface and lots of other stuff). It uses a (relatively) large external 4.7uH inductor and what appears to be quite a few other discrete (cheap) components. The only ICs are the SOC and two Toshiba TC58DVM92A1FT00 512Mb flash memory chips, the rest of the 150 or so parts are discretes, not even an IC audio amplifier.

(photos about 200K each on 0.2" quadrille paper)

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(the inductor is the large black square to the lower right of the SOC)

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-----

Best regards, Spehro Pefhany

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Spehro Pefhany

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