YAMAHA MUSIC CARTRIDGE

Hi,
Can anybody help me to find out the pinouts of Yamaha music cartride used in
PSR-520 keyboard? I opened one of these but it has a Yamaha Chip (XQ901AD),
for which I couldn't find any data. It will be greately appreciated if
someone can help me on either the pinouts or the datasheet of the actual
chip in the cartridge.

Thanks in advance,
Tharaka.