Hallo to all,

i am the one working on the STMPL3400 mp3 player chip,
so far i had no luck in finding any data on the chip.

Sniffing the USB bus under windows i had been able to collect some informations, i 
want to share some ideas with you.

The device seems to communicate only with bulk transfers, sending commands down the 
bus and receiving data from the device. Is this a common behaviour of usb devices?

After sending a couple of commands down the bus, i have isolated a string shich seems 
to cause the device to send a lot of data.
The string is something like:

0x0c0 0x00 0x80 0x01 0x00 0xZZ 0xZZ ....
in response to this command i get 1536 (0x600) bytes back fromn the device.
0xZZ 0xZZ seems to be an address because the windows drivers send this command in 
aloop asking for the following "addresses":
0x00 0x00
0x40 0x00
0x80 0x00
0xc0 0x00
0x00 0x01
...
0xc0 0x03

getting everytime 0x600 bytes back.


Well, if it is an address why do it get back 0x600 bytes instead of 0x40? I thought it 
may be something like "0x40 blocks" but 0x600/0x40 = 24bytes and a data block of 
24bytes seems strange.

Second, can be that data a fat? it doesnt seems like a fat to me, but what else can it 
be?
Why transferring more that 20kb of data trough the bus if it is not a file nor a fat?

My device had a SmartMedia card and some internal memory, so i wonder if having 
SmartMedia specifications can help me to understand better?

Please, some of you have more experiencde than me on this subjects, give some 
suggestions.

bye!


Willy Gardiol
[EMAIL PROTECTED]
gardiol.eu.org






-------------------------------------------------------
This sf.net email is sponsored by:ThinkGeek
Welcome to geek heaven.
http://thinkgeek.com/sf
_______________________________________________
[EMAIL PROTECTED]
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel

Reply via email to