Programmable Functional Elements of Xilinx Spartan 3E

Several platforms demand for optimal design solutions. Advancement in technology has contributed to growth in several areas. Also, the impact of these advancements is evident in the FPGA industry. Xilinx keeps designing several optimized platforms. The Xilinx Spartan 3E is an affordable I/O optimized solution for several applications.

What is Xilinx Spartan 3E?

The Spartan 3E is an FPGA designed by Xilinx. It is a family of Field Programmable Gate Arrays (FPGAs) designed to meet the demands of cost-sensitive and high-volume applications. Also, this FPGA family provides densities that range from 100,000 to 1.6 million system gates. The Spartan 3E increases the amount of logic per I/O. Therefore, it reduces the cost for each logic cell.

Also, there are new features that enhance system performance and minimize the configuration cost. With the improved 90nm process technology, Spartan 3E has been able to offer more functionality. Also, the bandwidth per dollar has increased. Therefore, this has created new standards in the programmable logic industry.

As a result of Spartan 3E’s low cost, this FPGA is a perfect choice for various consumer electronics applications. Also, the Spartan 3E FPGA is a better option to mask programmed ASICs. In addition, FPGA programmability allows design upgrades without the need for hardware replacement. This is impossible with ASICs.

Basic Programmable Functional Elements of Spartan 3E

Xilinx Spartan 3E
Xilinx Spartan 3E

Xilinx Spartan3E features five basic programmable functional elements which are:

Input/Output Blocks (IOBs)

These blocks are responsible for controlling data flow between the internal logic and I/O pins. Every IOB supports 3-state operation and bidirectional data flow. Also, each IOB features a programmable delay block that delays the input signal. Each IOB has three pairs of storage elements.

One pair is for each three paths. Also, you can configure each of the storage elements as a level-sensitive latch (LD) or a D-type flip-flop (FD).

Multiplier Blocks

The Spartan 3E FPGA offers 4 to 36 dedicated multiplier blocks for each device. These blocks accept two 18-bit binary numbers.  Also, multipliers stay together with the block RAM in one or two columns. Typically, multiplier blocks execute complement numerical multiplication. Also, they can carry out some less obvious applications like barrel shifting and data storage.

Furthermore, logic slices can implement small multipliers and supplement the dedicated multipliers. The dedicated multiplier blocks of Spartan 3E include more additional features. Every multiplier block features optional registers on every multiplier output and inputs. These registers are PREG, AREG, and BREG.

Configurable logic blocks (CLBs)

These blocks comprise Look-Up Tables (LUTs) that incorporate logic plus storage elements. Also, CLBs carry out various logical functions. The configurable logic blocks comprise the primary logic resource for integrating synchronous and combinatorial circuits. Every CLB comprises four slices. Every slice features two Look-Up Tables (LUTs) and two dedicated storage elements that can function as latches or flip-flops.

Also, the LUTs can serve as a 16×1 memory or a 16-bit shift register. CLBs are always in an array of columns and rows. Each density differs by the number of columns and rows of CLBs. Every CLB features four interconnected slices. These slices are in pairs. Therefore, each pair display as a column with a separate carry chain.

Block RAM

This element offers storage of data in 18-Kbit dual-port blocks. There are 4 to 36 dedicated block RAMs in Spartan 3E devices. These block RAMs are specially organized as dual-port configurable 18Kbit blocks. Also, the Block RAM stores much data. The distributed RAM is ideal for buffering small data along signal paths.

You can configure each block RAM by setting the initial values of the content and output registers’ default signal value. Also, block RAM is ideal for use in both dual-port and single-port modes.

Digital clock manager (DCM) blocks

These blocks offer self-calibrating digital solutions for multiplying, dividing, and delaying clock signals. Spartan 3E FPGA features eight, two, or four DCMs based on the size of the device. Also, the DCM in Spartan 3E offers complete control over phase shift and clock frequency. Therefore, the DCM integrates a Delay-Locked Loop (DLL) and a digital control system. This control system maintains precise clock signal characteristics by using feedback.

The digital clock manager of Spartan 3E supports three primary functions. Also, these functions are phase shifting, clock-skew elimination, and frequency synthesis. The DCM features three major components which are the Digital Frequency Synthesizer, the Phase Shifter, and the Delay-Locked Loop.

Types of Pins in Spartan 3E

Full pcb manufacturing

Spartan 3E FPGA features different types of pins. Most pins on this FPGA are user-defined I/O pins. However, there are about 11 different functional pin types on Spartan 3E packages.


The dual-purpose pin is ideal for use during the configuration process. Also, these pins are always available as a user I/O immediately after configuration. This pin will act as an I/O type pin if it isn’t used during configuration.


Each package features 16 global clock inputs that clock the whole device. Also, the RHCLK inputs clock the device’s right-half. The LHCLK inputs clock the device’s left-half.


The dedicated JTAG pin isn’t available as a user I/O pin. Also, each package features four dedicated JTAG pins. The VCCAUX powers these pins.


This is a general purpose input pin. Also, this pin doesn’t feature an output structure.


The dedicated ground pins are available in different numbers. The type of package used will determine the number of GND pins. However, all these pins must be well connected.


This is a dual-purpose pin ad it is either an input-only pin or user I/O pin. It offers a reference voltage input for particular I/O standards.


This pin distributes power to the output buffers within the I/O bank.


This is a dedicated auxiliary power supply pin. Also, the type of package used determines the number of these pins.

Common Applications of Xilinx Spartan-3E FPGA

The Spartan 3E FPGA is suitable for several applications. Also, this FPGA comprises many features which contribute to its high performance. Spartan 3E is ideal in applications such as :

  • Computer systems
  • Home networking
  • Broadband access
  • Display/projection
  • Vehicle network system

What are the Spartan 3E FPGA Devices?

XC3S500E-5PQG208I XC3S500E-5FTG256C XC3S500E-5PQ208I

XC3S500E-5FG320C      XC3S500E-4VQG100I   XC3S500E-5CPG132C

XC3S500E-4VQ100C      XC3S500E-4PQG208I XC3S500E-4VQG100C

XC3S500E-4PQG208C  XC3S500E-4PQ208C XC3S500E-4PQ208I

XC3S500E-4FTG256I XC3S500E-4FGG320I XC3S500E-4FTG256C

XC3S500E-4FGG320C  XC3S500E-4FG320C    XC3S500E-4CPG132C

XC3S250E-5TQ144 XC3S250E-5FTG256C XC3S250E-5PQG208C

XC3S250E-4VQG100C    XC3S250E-4TQG144C XC3S250E-4VQG100I

XC3S250E-4TQ144I XC3S250E-4PQ208C XC3S250E-4TQ144C

XC3S250E-4FTG256I   XC3S250E-4FT256C XC3S250E-4FTG256C

XC3S250E-4CPG132C    XC3S1600E-5FGG320C    XC3S1600E-4FGG484C

XC3S1600E-4FGG400I XC3S1600E-4FGG320I XC3S1600E-4FGG400C

XC3S1600E-4FGG320C XC3S1200E-4FTG256I XC3S1200E-5FT256C

XC3S1200E-4FTG256C XC3S1200E-4FGG400C XC3S1200E-4FGG400I

XC3S100E-5VQ100C XC3S100E-4VQG100I  XC3S1200E-4FGG320I

XC3S100E-4VQG100C XC3S100E-4TQG144C XC3S100E-4VQ100C

XC3S500E-4CP132CES XC3S500E-5PQ208C XC3S500E-FTG256DGQ

XC3S500E-FGG320 XC3S500E-5FT256C XC3S500E-5PQG208C

XC3S500E-5FGG320C XC3S500E-4VQ100I   XC3S500E-5CP132C


Here comes the Programmable Functional Elements of Xilinx Spartan 3E. Please check our blog section for more interesting articles.

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