Xilinx Frequency Generator - Manual

Frequency Generator for the Spartan-3E Starter Kit 5 PicoBlaze Design Size The images and statistics on this page show that the design occupies just 172 slices, 1 BRAM and 2 DCMs. This is only 3.7% of the slices available in an XC3S500E device. More significantly, this slice count can be reduced to ...

Frequency Generator for the Spartan-3E Starter Kit 6 Design Files The source files provided for the reference design are….. frequency_generator.vhd Top level file and main description of hardware. Contains I/O required to disable StrataFLASH memory device on the board which may otherwise interfere w...

Frequency Generator for the Spartan-3E Starter Kit 7 Direct Digital Synthesis (DDS) Circuit Diagram 32-Bit Counter CLKIN 50MHz clk BUFG phase_acc_dcm DCM The first DCM is used to multiply the 50MHz clock by a factor or 4 and form a 200MHz clock. This gives the phase accumulator a timing resolution o...

Frequency Generator for the Spartan-3E Starter Kit 8 PicoBlaze Circuit Diagram strataflash_oe strataflash_ce strataflash_we Vcc * ** * StrataFLASH memory must be disabled to prevent interference with the LCD display. interrupt_control ‘JTAG_loader’ allows rapid PicoBlaze code development. port_id kc...

Frequency Generator for the Spartan-3E Starter Kit 9 Phase Accumulator Waveforms The following waveforms were obtained by monitoring the output of the phase accumulator presented on stake pin ‘J4-IO9’. In each case the digital storage oscilloscope was set to infinite persistence in order capture any...

Frequency Generator for the Spartan-3E Starter Kit 10 Phase Accumulator Spectrum An alternative way to observe the quality of the waveforms synthesised by the phase accumulator is to look at the frequency spectrum. I was lucky enough to have a 2048-point FFT feature on my oscilloscope which allows s...

Frequency Generator for the Spartan-3E Starter Kit 11 Final Output Waveforms These waveforms were obtained from stake pin ‘J4-IO12’ and reflect the final output of the frequency generator. Once again the digital storage oscilloscope was set to infinite persistence in order capture any fluctuations o...

Frequency Generator for the Spartan-3E Starter Kit 12 Final Output Spectrum Observing the frequency spectrum of the final output reveals that you can not get something for nothing and helps us to understand when the frequency aligned mode should and should not be used. I have used the infinite persi...

Frequency Generator for the Spartan-3E Starter Kit 13 Setting DCM Frequency Aligned Mode To set the DCM into the frequency aligned mode of operation a special option must be used during configuration file generation. This can be set in the ISE tools as shown in these screen shots from an ISE v8.1i p...

Frequency Generator for the Spartan-3E Starter Kit 14 Exercises, Experiments and Suggestions Here are some exercises, experiments and suggestions for you to consider based on this reference design. Although several are specific to the Spartan- 3E Starter Kit, most are portable to your own boards and...