Design Overview

Output Frequency provided on SMA socket

This design converts the Spartan-3E Starter Kit into a reasonably accurate frequency generator covering the nominal range 1Hz to 100MHz. The design allows you to attempt generation of higher frequencies to allow you to experiment with the maximum performance of the Spartan device on your board. The rotary control is used to edit the frequency displayed on the upper line of the LCD display and the corresponding frequency will then be output on the SMA connector (J17) as well as the stake pin J4-IO12. Internally to the device the frequency range is twice that provided externally (nominally up to 200MHz).

As well as providing the basic instructions to use the frequency counter, this document provides details of the Direct Digital Synthesis (DDS) techniques used in the design such that the can be transplanted into your own designs. PicoBlaze is used to provide the human interface and perform so high precision calculations which are passed to a simple but high performance (200MHz) frequency synthesizer formed from pure hardware and two Digital Clock Managers (DCMs). The lower line of the LCD display provides the information passed from PicoBlaze to the hardware which means that you can use this design with your board to determine the exact values required to implement a fixed frequency synthesizer without requiring PicoBlaze, the knob and LCD display. On this board the technique provides a convenient alternative to fitting a special oscillator in the IC16 socket and it may proves a cost effective solution for many real product applications too.

Load it now – it only takes 30 seconds!

It is recommended that you try this to become familiar with what the design does (operating instructions on the next page).

As well as the source design files, a compiled configuration bit file is provided which you can immediately download into the Spartan XC3S500E device on your board. To make this task really easy the first time, unzip all the files provided into a directory and then….

double click on ‘install_frequency_generator.bat’.

Assuming you have the Xilinx software installed, your board connected with the USB cable and the board powered (don’t forget the switch), then this should open a DOS window and run iMPACT in batch mode to configure the Spartan-3E with the design.

	Spartan XC3S500E	50MHz Reference
	Spartan XC3S500E	Crystal Oscillator
		Crystal Oscillator

Press and rotate knob	DDS control values
to set frequency	(bottom line)

J4-IO9

Phase

Accumulator

Test Point

J4-IO12

Copy of Output

Frequency

LEDs indicate

frequency

editing mode

Frequency display

(top line)

Frequency Generator for the Spartan-3E Starter Kit 3

Frequency Generator specifications

The Xilinx Frequency Generator is a versatile and robust solution designed for a variety of applications requiring precise frequency generation and control. This device capitalizes on Xilinx's proven technology in programmable logic, enabling engineers to implement custom frequency generation schemes tailored to specific application needs.

One of the main features of the Xilinx Frequency Generator is its flexible frequency range. It supports a wide spectrum of frequencies, making it suitable for applications in telecommunications, aerospace, automotive, and industrial automation. The ability to generate frequencies from kilohertz to gigahertz opens up possibilities for diverse scenarios, such as clock generation, signal synthesis, and modulation tasks.

Another significant characteristic of this frequency generator is its programmability. Leveraging Xilinx's FPGA architecture, users can easily configure and program the frequency generator to meet changing requirements. This programmability allows for rapid prototyping and design iterations, enabling engineers to achieve optimal configurations with minimal downtime.

The device also employs advanced phase-locked loop (PLL) technology, ensuring excellent stability and low phase noise. PLLs enable the generation of output frequencies that are phase-coherent with an input signal, which is critical for applications requiring precise synchronization. This feature is especially beneficial in communication systems, where accurate timing and frequency stability are essential.

Furthermore, the Xilinx Frequency Generator supports multiple output formats, including sinusoidal, square, and triangle waves. This versatility in signal output enhances its usability across different applications, allowing for easy integration into existing systems.

Another innovative aspect of this frequency generator is its integration with Xilinx's software tools, such as Vivado and ISE. These tools facilitate the design, simulation, and implementation of frequency generation strategies, enhancing productivity and ensuring robustness in design processes.

In addition, the frequency generator's power efficiency is noteworthy. By employing cutting-edge low-power design techniques, it reduces energy consumption without compromising performance, making it an ideal choice for battery-powered or energy-sensitive applications.

All in all, the Xilinx Frequency Generator exemplifies cutting-edge technology in frequency generation, offering flexible configuration, excellent stability, and user-friendly integration, making it a compelling choice for engineers across various industries seeking a reliable frequency generation solution.