www.megadrum.info

Hi, it's me again. I saw from the pictures posted that the digital board uses an optocoupler that has only 4 pins which leads me to believe this is not 6N138 (which has 8 pins). Did you use a substitute since you're not using midi in as seen in the picture? What substitute can I use if I only need to put midi out?

Thanks!

Do I understand you right that you don't want to use MIDI in? In that case you can exclude 6N138 altogether along with directly connected to it resistors, a diode and "MIDI in" socket.

Regards

Yes, I don't want to use MIDI in. Thanks for clearing that out.

I have another question, what is the purpose of the USB EXT and the ISP socket in the schematic?

"USB Ext" is used by an optional AVD-CDC USB or FT232 USB board if want not only power MegaDrum over USB but also transmit MIDI over it.
ISP Socket is used to write firmware form a PC into Atmega8/32 over "ISP Programming cable". See "Firmware" section on the Docs&Faqs page.

Btw, how is it going? Have you already soldered anything?

Regards

Wow! Thanks for the quick answers. I haven't soldered anything yet. Me and my friend are still trying to understand the schematics as we'd like to build all the boards needed. If we do get to build the boards, we'll send you the files so we can share it to everyone.

Thanks again for this nice project.