Hi trash80! ... Well I didn't change the code that way and that's why... Later when I tried usb mode I use the default code.
I see what you mean. Basically problem is solved^^ Thanks to all!

If the lights flash to incoming midi data than the sparkfun shield's midi circuit is working. Also how did you change the pin numbers for the gameboy data pins in the code? It is all done by sending data directly to the port so I'd imagine you'd have to do quite a bit in a few places ie ... from:

   if(send_byte & 0x80) {
       PORTC = B00000010;
       PORTC = B00000011;
   } else {
       PORTC = B00000000;
       PORTC = B00000001;
   }

to this:

   if(send_byte & 0x80) {
       PORTC = B00001000;
       PORTC = B00001100;
   } else {
       PORTC = B00000000;
       PORTC = B00000100;
   }

Have you tried having it plugged into usb just for power and still use the MIDI input?

Here's some updates. I tried the usb mode as blogged here: http://txton.net/hoehoe/2010/100511030849.html
Everything works! So I think it might be the sparkfun midi shield's 'midi in' problem(I tested the midi out, seems fine). Either it could be a connection problem or the shield itself... Any thoughts?

http://www.sparkfun.com/products/9595 here is the right link. 404 due to the point in the end.

Link goes to a 404, heads up.

Anyone please???

Hi all, I'm new here:)

I recently built an Arduinoboy by following the Instructables' guide. I used the sparkfun's midi shield: http://www.sparkfun.com/products/9595. As the shield use analog 0 and 1 I changed the Arduinoboy code by assigning the pins to 2,3,4 for the gameboy cable instead of 0,1,2. The circuit should be right... The LEDs flash and I can switch modes.

However when I tried the mGB mode as the guide said, no sound comes out from the gameboy advance (with an EMS cart). I also noticed that under mGB mode when I hit keys on my m-audio instrument (m-audio send midi signal to Arduino), the LED 12 blinks indicating midi channel one active though no sound. But when I changed to channel 2, no LED blinks, same for the other channels. What did I do wrong? I haven't tried other modes yet. Besides, when I turn up gameboy I can no longer loop back to previous mode, any thoughts? Hope these questions are not too stupid.

Someone kind enough to help me out:)
Thanks in advance!