The bus of the ORDINATOR is an extended Z80 processor bus. The extensions
add power voltages not required by the Z80 chip itself, extend the address
space from 64K to 512K and support a modular interrupt system.
bus layout
After some mistakes, the bus layout was finally "nailed to the wall"
(well, the front of the system) to make it universally accessible.
bus layout (click to enlarge)
Note the peculiar placement of the A18 address
line; this was added in late 1985 when the physical address space
was doubled from 256K to 512K.
