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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
 
S

Spehro Pefhany

Jan 1, 1970
0
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

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)
http://server2.hostingplex.com/~zstoretr/mp3top.jpg

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

http://server2.hostingplex.com/~zstoretr/mp3bot.jpg

http://www.toshiba.com/taec/components/Datasheet/TC58DVM92A1FT_030110.pdf


http://www.sigmatel.com/documents/App-Brief1-Flash-MP3-7-1.pdf
-----



Best regards,
Spehro Pefhany
 
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