Build a PIC controlled DDS VFO, 0 to 6 MHz using pic microcontroller




Files contained in MINIDDS.ZIP:

  readme.txt      Read this first!
compplac.pdf    Component placement in PDF format
schema.pdf      Schematic diagram in PDF format
top.ps          PCB top copper layer in Postscript format
bottom.ps       PCB bottom copper layer in Postscript format
ad9832_4.asm    PIC assembly source code
p16f84.inc      Needed for assembly of ad9832_4.asm (for 'F84)
p16c84.inc      As above but for 'C84
vfo5x7f.hex     PIC16F84 program for LCD with 5x7 font
vfo5x10f.hex    PIC16F84 program for LCD with 5x10 font
vfo5x7c.hex     PIC16C84 program for LCD with 5x7 font
vfo5x10c.hex    PIC16C84 program for LCD with 5x10 font
filtresp.pcx    Computed frequency response of lowpass filter

Build a PIC controlled DDS VFO, 0 to 6 MHzDownload MINIDDS.ZIP (186K)

Download MINIDDS.PDF (209K)

If you prefer to control the DDS module from a PC (instead of using a PIC), try this:

Download PCVFO.ZIP (18K)

The zip archive contains a single file, VFO.EXE. It is a DOS program but it runs fine in a Windows 95/98 “DOS bubble” as well (see screenshots above).

Are you looking for a DDS based 136 kHz longwave transmitter exciter?

Have a look at G0MRF’s page

Specifications:

  • Start-up frequency: 137.00000 kHz
  • Tuning range: 135.70000 to 137.80000 kHz in 0.25 Hz steps
  • DFCW offset: 0 to 50 Hz adjustable in 0.25 Hz steps
  • The dial can be locked to prevent inadvertent QSY
  • Calibration: +/- 200 ppm, stored in EEPROM.
  • Actual DDS output frequency is 4 * dial frequency

Schematic and source code for the PIC controller is available here:

Download the PIC program lwex.zip

The PIC program is written for the free version of the CC5X C compiler which is available at www.bknd.com
Build a PIC controlled DDS VFO, 0 to 6 MHzAlmost any 2×16 character LCD module with Hitachi HD44780 controller chip will work. The LCD pin numbers on the schematic are not valid for all LCD modules. Please check the actual signal names on your particular LCD module.
The selected DFCW frequency offset will be added to the output frequency when the DFCW input is grounded. This input has a weak pull-up in the PIC.

READ  Parallel Port Microchip PIC Micro Controller Programmer

The encoder inputs also have internal pull-ups in the PIC.

The switches “LOCK”, “DFCW” and “CAL” are momentary pushbuttons.

 

For more detail: Build a PIC controlled DDS VFO, 0 to 6 MHz




Current Project / Post can also be found using:

  • vfo com pic

Leave a Comment

*
= 5 + 7

Read previous post:
PIC 18F4550 Motor Controller Video Project
PIC 18F4550 Motor Controller Video Project

In this video, we cover how to breadboard and write the firmware for a motor controller (controlling a servo, 2...

Close
Scroll to top