Xilinx Pico Blaze Frequency Generator Owner'S Manual Download Page 6

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 with the LCD display.

PicoBlaze program source assembler code

kcpsm3.vhd

PicoBlaze processor for Spartan-3E devices.

fg_ctrl.vhd

frequency_generator.ucf

I/O constraints file for Spartan-3E Starter Kit 

Timing specifications for 50MHz PicoBlaze controller 200MHz DDS circuits.

Location constraint for DCM used for Jitter reduction.

fg_ctrl.psm

Assembled program for PicoBlaze (stored in a Block memory) 

Note: The file shown in 

green

is not included with the reference design as it is provided with PicoBlaze download. Please visit the PicoBlaze Web site 

for your free copy of PicoBlaze, assembler, JTAG_loader and documentation. 

www.xilinx.com/picoblaze

Hint – The JTAG_Loader utility supplied with PicoBlaze has been included in this design. This enables the new programs to be written for PicoBlaze 

using the configuration file provided.

This design contains an otherwise undocumented and unspecified mode of 

operation for a DCM. Before this design can be processed a special BITGEN option 

needs to be set. Please read the notes provided on page 13 as well as those 

contained in ‘frequency_generator.vhd' for details of this special requirement.  

Hint – You do not need PicoBlaze if you use this design as the basis for implementing a fixed frequency module. However, I’m sure you will want 

PicoBlaze for other parts of your design now that you have seen what it is capable of doing  .

Summary of Contents for Pico Blaze Frequency Generator

Page 1: ...Frequency Generator for Spartan 3E Starter Kit Ken Chapman Xilinx Ltd 18th July 2006 Rev 1 With special thanks to Peter Alfke and Alireza Kaviani...

Page 2: ...iable for any loss of data lost profits cost or procurement of substitute goods or services or for any special incidental consequential or indirect damages arising from the use or operation of the des...

Page 3: ...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...

Page 4: ...ck line under the digit in the top line Edit digit value mode Press and release knob to toggle between frequency editing modes Edit cursor position mode In this mode rotating the knob to the left or r...

Page 5: ...frequency version Number of occupied Slices 172 out of 4 656 3 Number of Block RAMs 1 out of 20 5 DCMs 2 out of 4 50 Total equivalent gate count for design 91 537 PicoBlaze makes extensive use of the...

Page 6: ...included with the reference design as it is provided with PicoBlaze download Please visit the PicoBlaze Web site for your free copy of PicoBlaze assembler JTAG_loader and documentation www xilinx com...

Page 7: ...ecimal so the output from the phase accumulator is 9 5MHz a period of approximately 105ns That means that the accumulator synthesizes one output cycle for approximately 21 cycles of the 200MHz clock f...

Page 8: ...led 3 led 2 led 1 led 0 led 7 output_ports rotary_a rotary_press rotary_b lcd_rs lcd_e lcd_rw lcd 7 6 lcd 6 lcd 5 lcd 4 lcd 7 lcd 6 lcd 5 lcd 4 bidirectional LCD data rotary_press_in See reference de...

Page 9: ...cycles 200MHz 8 cycles 200MHz This waveform shows what happens when you try to synthesize a 12 4125MHz clock using the phase accumulator There is clearly 5ns of cycle to cycle jitter in this situatio...

Page 10: ...ynthesis process and this is reflected by a distinct 12 5MHz component which is 45dB above the noise floor The zoomed plot shows how the fundamental covers only a narrow bandwidth keeping in mind that...

Page 11: ...mode you must accept that it does NOT maintain phase lock as it does in all other normal modes More significantly the output frequency is the average of the input frequency which means there will oft...

Page 12: ...tay balanced because we are unable to freeze completely due to other influences on us and the need to breath etc 12 5MHz Fundamental 5MHz division 10dB division 1MHz division 10dB division 3rd Harmoni...

Page 13: ...mming File Then right click and select Properties to open the Process Properties box 2 The Process Properties box should open with the General Options being shown otherwise select General Options on t...

Page 14: ...frequencies you require then reduce the design to a phase accumulator driven by a constant N the DCMs and a fixed counter divider no multiplexer Hint If you still operate the phase accumulator at 200...

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