Figure 7.9 shows the Altera MAX 9000 interconnect architecture. The size of the MAX 9000 LAB arrays varies between 4 ¥ 5 (rows ¥ columns) for the EPM9320 and 7 ¥ 5 for the EPM9560. The MAX 9000 is an extremely coarse-grained architecture, typical of complex PLDs, but the LABs themselves have a finer structure. Sometimes we say that complex PLDs with arrays (LABs in the Altera MAX family) that are themselves arrays (of macrocells) have a dual-grain architecture .
In Figure 7.9 (b), boxes A, B, and C represent the interconnection between the FastTrack buses and the 16 macrocells in each LAB:
- Box A connects a macrocell to one row channel.
- Box B connects three column channels to two row channels.
- Box C connects a macrocell to three column channels.