The document describes the Xilinx 4000 series FPGA. It consists of configurable logic blocks (CLBs) connected through a programmable interconnect structure. Each CLB contains logic elements, flip flops, and configurable function generators. The interconnect structure includes direct connections between neighboring CLBs as well as general routing resources. Input/output blocks around the perimeter provide external connectivity. FPGAs offer advantages like rapid design times, flexibility for updates, and lower costs compared to ASICs, though ASICs can provide higher performance.
Xilinx 4000 SeriesFPGA
ME- Applied Electronics(PT)
Department Of Electrical And Electronics Engineering
PSG College of Technology (Autonomous)
Coimbatore
CLB:
2 FF perCLB + 2 per I/O cell
25 gates per CLB for logic
32 bits of SRAM per CLB
Special fast carry logic between CLBs
Interconnects:
Direct and general-purpose wires replaced with more efficient single-
length and double-length lines.
Sufficient resources for most applications
Features:
Synchronous Single and Dual-Port RAM
Internal Three-state buffers.
System performance to 80 MHz
0.5 µ SRAM Process Technology
5.
Logic blocks (CLB)
*configurablelogic block, logic element, logic module, logic unit,
logic array block,
*to implement combinational and sequential logic
Interconnect
*wires to connect inputs and outputs to logic blocks
I/O blocks
*special logic blocks at periphery of device for external connections
7.
CLB - ConfigurableLogic Block
* 5-input, 1 output function
* 2 4-input, 1 output functions
* optional register on outputs Built-in fast carry logic
Can be used as memory
Three types of routing
* direct
* general-purpose
* long lines of various lengths
RAM-programmable
* can be reconfigured
8.
Use RAM fortruth tables
* F, G: 4 input -> 16 bits of RAM (each)
* H: 3 input –> 8 bits of RAM
* RAM is loaded at system initialization from
external PROM
MUX control logic maps 4 control inputs into 4 inputs:
* LUT input H1
* Direct In (DIN)
* Enable Clock (EC)
* Set/Reset control (S/R) for FFs
•Control F,G LUTs as 32 bit SRAM
Broad capability:
*Any 2 functions of 4 variables plus a function of 3 variables
*Any function of 5 variables
*Any function of 4 variables plus some functions of 6 variables
*Some functions of 9 variables
* Parity
*4-bit case cadable equality checking
11.
Output:
Combinational or registered;
director inverted
Input:
combinational. Or registered;
zero hold
time option
Internal FFs for input & output
paths
Fast/Slow outputs
5 ns vs. 30 ns rise
Pull-up/down
used with
unused IOBs
3 types:
* FastDirect Connections
* General Purpose Connections
with Switching Matrix
*Horizontal/Vertical Long
Lines
Types of lines:
* Single length (8)
* Double length (4)
* Long lines (6)
* Global lines (4)
15.
Direct interconnect:
Adjacent CLBsare wired together in the horizontal or vertical
direction. The most efficient interconnect (< 1 ns delay)
General-purpose interconnect:
used mainly for longer connections or for signals with a
moderate fan-out
Few, so problem in fitting a large design intoXC3000, and 2000
Long line interconnect:
for time critical signals (e.g.clock signal need be distributed to
many CLBs
16.
*Between neighboring locks
*FromCLB to CLB
*From CLB to IOB
*Fastest, short distance
connections
*X: Horizontal Connection
* Y: Vertical connection
21.
Implementation of randomlogic
*easier changes at system-level (one device is modified)
* can eliminate need for full-custom chips
Prototyping
* ensemble of gate arrays used to emulate a circuit to be
manufactured
* get more/better/faster debugging done than possible with
simulation
Reconfigurable hardware
* one hardware block used to implement more than one function
*functions must be mutually-exclusive in time
* can greatly reduce cost while enhancing flexibility
* RAM-based only option
Special-purpose computation engines
* hardware dedicated to solving one problem (or class of problems)
*accelerators attached to general-purpose computers
22.
*Faster than CPUsolution
*Lower power than CPU solution (usually)
*Low NRE costs
*Off-the-shelf part designed by FPGA vendor
*You are sharing NRE costs with all other customers
*Fast design time
*Low time-to-market
*Fast re-design / re-fabrication time
*Easy to correct an error, to add functionality, in
response to spec change
*Can even change product after deployment
*Good for low to middle volume applications
23.
*High per-part costs
*Highvolume applications should consider ASICs
*Perhaps use FPGA for prototyping
*Lower performance than ASIC
*Higher power than ASIC
*More specialized design skills than CPU