I had some spare time to work on that issue.
I soldered a couple of pins to make it easier to connect/disconnect the rMP3. It works well, the only things is that it is confusing that the Tx/Rx pins on the solderable pads must be connected to the Rx/Tx of the arduino serial pins respectively (it must be a crossed cable). Apart from this point, I like this system, it is very flexible.
So I connected everything and modified a simple script to play a tune with the rMP3 using the serial port, and it works very well at 9600 but still fails at 57600. Basically, when I change the option D0 to D3 with the correct serial baudrate, the music does not start. Here is the setup function:
void setup()
{
delay(2000);
Serial.begin(9600); // initialise the serial rMP3 connection
rmp3.print("ST D0"); // if changed to D3, the module fails
delay(100);
Serial.begin(9600); // that would be changed to 57600
delay(100);
rmp3.sync();
rmp3.stop();
rmp3.setvolume(volume);
filecommands.sync();
// mix up our random number generator
randomSeed(analogRead(0));
updateSongList();
}
I suspect that the sync is still a problem. Any suggestion?