6
AT94KAL Series FPSLIC
Rev. 1138G–FPSLI–11/03
The Busing
Network
Figure 3.
Busing Network
Figure 4 depicts one of five identical FPGA busing planes. Each plane has three bus
resources: a local-bus resource (the middle bus) and two express-bus resources. Bus
resources are connected via repeaters. Each repeater has connections to two adjacent local-
bus segments and two express-bus segments. Each local-bus segment spans four cells and
connects to consecutive repeaters. Each express-bus segment spans eight cells and
bypasses a repeater. Repeaters regenerate signals and can connect any bus to any other bus
(all pathways are legal) on the same plane. Although not shown, a local bus can bypass a
repeater via a programmable pass gate, allowing long on-chip tri-state buses to be created.
Lo ca l /l oc al tu r ns ar e im pl e m e nte d th ro ug h p as s g a tes i n the c el l -b us i nt er fac e.
Express/express turns are implemented through separate pass gates distributed throughout
the array.
= I/O Pad
= AT40K Cell
= Repeater Row
= Repeater
= RAM Block
Interface to AVR