Both FPGAs share the same overall routing structure. The basic fanin/fanout structure (a) is augmented with segmented routing channels (b) attached to a third RLB (Routing and Logic Block) input and output. The structure (c) is obtained by merging two copies of (b), with data flowing in opposite directions in the two copies. Shown in (d) are the connections between the two copies at diagonal crossings.
The RLB consists of 3 multiplexors for the inputs, a functional unit, 3 multiplexors for the outputs, and tristate drivers for the segmented channels. In Triptych, the functional unit is a 3-input lookup table (LUT), with an optional D-latch on it's output.
Montage has two different functional units. The most common (left) is similar to Triptych's, with a LUT and a D-Latch. The D-latch in Montage has a choice of two clocks to allow synchronous interfaces to be mapped, as well as a mode for initializing asynchronous stateholding functions. There is also a feedback line for implementing asynchronous stateholding functions. 1/16 of all functional units are arbiter blocks (right), which are capable of implemeting an arbiter, enabled arbiter, or synchronizer, with all inputs permuteable and invertable.
G. Borriello, C. Ebeling, S. Hauck, S. Burns, "The Triptych FPGA Architecture" (PDF), IEEE Transactions on VLSI Systems, Vol. 3, No. 4, pp. 491-501, December, 1995.
C. Ebeling, L. McMurchie, S. Hauck, S. Burns, "Mapping Tools for the Triptych FPGA" (PDF), IEEE Transactions on VLSI Systems, Vol. 3, No. 4, pp. 473-482, December, 1995.
E. A. Walkup, S. Hauck, G. Borriello, and C. Ebeling, "Routing-directed Placement for the Triptych FPGA" (PDF), ACM/SIGDA Workshop on Field-Programmable Gate Arrays, Berkeley, February, 1992.
S. Hauck, G. Borriello, S. Burns and C. Ebeling, "Montage: An FPGA for Synchronous and Asynchronous Circuits" (PDF), 2nd International Workshop on Field-Programmable Logic and Applications, Vienna, August 1992. Also appearing in H. Grunbacher, R. W. Hartenstein, Eds., Field-Programmable Gate Arrays: Architectures and Tools for Rapid Prototyping, Berlin: Springer-Verlag, pp. 44-51, 1993.