I am having some problems connecting 512MBytes of DDR2 to the L138. It looks like the row/col address bus is limited to 14 bits (A0-13). That would require a sinlge x16 device since x8 devices appear to have 15 address bits (A0-14). If that is the case, currently the only x16 4Gbit parts are very expensive twin die parts.
Is there a method of connecting (2) 256MByte x8 devices of DDR2 to the L138?