Digital Signal Processing Reference
In-Depth Information
3.7 Applications of FPGAs
The last decade has seen ever increasing application areas for FPGAs. A recent
market study found over twelve times as many new FPGA-based designs as
ASIC-based designs, and ASIC setup costs continue to increase. New
generation FPGAs can have nearly ten million gates with clock rates
approaching 1GHz. Example application areas include single chip replacements
for old multichip technology designs, Digital Signal Processing (DSP), image
processing, multimedia applications, high-speed communications and
networking equipment such as routers and switches, the implementation of bus
protocols such as peripheral component interconnect (PCI), microprocessor
glue logic, co-processors, and microperipheral controllers.
Several large FPGAs with an interconnection network are used to build
hardware emulators. Hardware emulators are specially designed commercial
devices used to prototype and test complex hardware designs that will later be
implemented on gate arrays or custom VLSI devices. Hardware emulators are
commonly used to build a prototype quickly during the development and
testing of microprocessors. Several of the recent Intel and AMD processors
used in PCs were tested on FPGA-based hardware emulators before the full
custom VLSI processor chip was produced.
A newer application area is reconfigurable computing. In reconfigurable
computing, FPGAs are quickly reprogrammed or reconfigured multiple times
during normal operation to enable them to perform different computations at
different times for a particular application.
3.8 Features of New Generation FPGAs
Each new generation of FPGAs increases in size and performance. In addition
to more logic elements, embedded memory blocks, and interconnects, other
new features are appearing. Some FPGAs contain a mix of both product term
and lookup tables to implement logic. Such product term structures typically
require less chip area to implement the complex gating logic present in large
state machines and address decoders. Many FPGAs include several phase-
locked loops (PLLs). These PLLs are used to multiply, divide, and adjust high-
speed clock signals. Similar to microprocessors used in PCs, many new FPGAs
use a lower 1.5 to 3 Volt internal core power supply. To easily interface to
external processor and memory chips, new FPGAs feature selectable I/O
standards on I/O pins.
High-speed hardware multipliers and multiply accumulators (MACs) are also
available in FPGA families targeted for multiply intensive DSP and graphics
applications. Several FPGAs from Altera and Xilinx are available with
commercial internal RISC microprocessor intellectual property (IP) cores.
These include the Nios, ARM, Microblaze, and PowerPC. The Nios and
Microblaze processors are an HDL model that is synthesized using the FPGA's
standard logic elements. The ARM, and PowerPC are commercial IP cores with
custom VLSI layouts. These new devices are a hybrid that contains both ASIC
and FPGA features. Several processors can be implemented in a single FPGA.
