Architectural overview – Xilinx DS610 User Manual
Page 3
Spartan-3A DSP FPGA Family: Introduction and Ordering Information
DS610 (v3.0) October 4, 2010
Product Specification
3
Architectural Overview
The Spartan-3A DSP family architecture consists of five fundamental programmable functional elements:
•
XtremeDSP™ DSP48A Slice provides an 18-bit x
18-bit multiplier, 18-bit pre-adder, 48-bit
post-adder/accumulator, and cascade capabilities for
various DSP applications.
•
Block RAM provides data storage in the form of
18-Kbit dual-port blocks.
•
Configurable Logic Blocks (CLBs) contain flexible
Look-Up Tables (LUTs) that implement logic plus
storage elements used as flip-flops or latches. CLBs
perform a wide variety of logical functions as well as
store data.
•
Input/Output Blocks (IOBs) control the flow of data
between the I/O pins and the internal logic of the
device. IOBs support bidirectional data flow plus
3-state operation. Supports a variety of signal
standards, including several high-performance
differential standards. Double Data-Rate (DDR)
registers are included.
•
Digital Clock Manager (DCM) Blocks provide
self-calibrating, fully digital solutions for distributing,
delaying, multiplying, dividing, and phase-shifting clock
signals.
These elements are organized as shown in
Figure 1
. A dual
ring of staggered IOBs surrounds a regular array of CLBs.
The XC3SD1800A has four columns of DSP48As, and the
XC3SD3400A has five columns of DSP48As. Each
DSP48A has an associated block RAM. The DCMs are
positioned in the center with two at the top and two at the
bottom of the device and in the two outer columns of the 4 or
5 columns of block RAM and DSP48As.
The Spartan-3A DSP family features a rich network of
routing that interconnect all five functional elements,
transmitting signals among them. Each functional element
has an associated switch matrix that permits multiple
connections to the routing.
X-Ref Target - Figure 1
Figure 1: Spartan-3A DSP Family Architecture
CLB
Block RAM
DCM
IOBs
IOBs
DS610-1_01_031207
IOBs
IOBs
DCM
Block RAM / DSP48A Slice
DCM
CLBs
IOBs
DSP48A Slice
Notes:
1.
The XC3SD1800A and XC3SD3400A have two DCMs on both the left and right sides, as well as the two DCMs at the top and
bottom of the devices. The two DCMs on the left and right of the chips are in the middle of the outer Block RAM/DSP48A
columns of the 4 or 5 columns in the selected device, as shown in the diagram above.
2.
A detailed diagram of the DSP48A can be found in
XtremeDSP DSP48A for Spartan-3A DSP FPGAs User Guide.