... inter-rupts, insert wait states, and so forth.EXTERNAL RAMThe external RAM is a classic32-KB fast asynchronous SRAM with a 15-ns access time (tAA). Its pins in- clude A1 4:0 (address), D7:0 (data in/ out), ... make ease-of-use tradeoffs in favor of core users.Because FPGAs are malleable andFPGA SoC design is so new, I wantedan interface that can evolve to addressnew requirements without invalidat-ing ... XD7:0.During a RAM read, XDOUTT isdeasserted, RAMNOE is asserted, andthe RAM drives its output data ontoXD7:0. The data is input through theIBUFs and latched in the XDIN IFDs(on each falling...