An interesting technique for doing FIFO design is to perform asynchronous comparisons between the FIFO write and read pointers that are generated in clock domains that are asynchronous to each other. The asynchronous FIFO pointer comparison technique uses fewer synchronization flip-flops to build the FIFO. The asynchronous FIFO comparison method requires… (More)
1 Summary Shift registers longer than eight bits can be implemented most efficiently in XC4000E Select-RAM TM. Using Linear Feedback Shift-Register (LFSR) counters to address the RAM makes the design even simpler. This application note describes 4-and 5-bit universal LFSR counters, very efficient RAM-based 32-bit and 100-bit shift registers, and… (More)
As CMOS devices follow the technology road map to ever smaller geometries, several undesirable effects have become apparent. These are: • Soft Errors • Wear-out Mechanisms: • Hot Carrier Injection (HCI) • Time Dependent Dielectric Breakdown (TDDB) • Negative Bias Temperature Instability (NBTI) • Latchup Each issue is reviewed with respect to its effect on… (More)
SRAM-based high-density FPGAs offer many advantages in satellite and other aerospace applications. A perceived drawback is the susceptibility of configuration latches to radiation-induced upsets. Heavy-ion testing at Brookhaven have established that the specially processed Xilinx XQR4000XL-family devices exhibited latch-up immunity at LET>100 MeVcm 2 /mg at… (More)
Field-programmable logic started out as glue logic between Òreal ICs.Ó Over the past decade, however, progress in IC technology has made it possible to implement ÒrealÓ functions in FPGAs. Now, bigger and faster FPGAs are becoming system platforms that combine several ÒrealÓ systems functions on a single chip. even microprocessors and memories. ÒBiggerÓ… (More)
All Virtex® and Spartan® FPGAs include many block RAMs. Even the smallest Virtex device has dozens of block RAMs, larger devices have hundreds, and the largest, the XC5VSX240T, has 1032. Because many designs do not require all of these block RAMs, this paper explores alternate uses for these functional blocks.