News, Updates and Other Minutiae
September 2023 Long time between drinks, but not much happening on the tech front at the moment. Added another couple of rants to the rant page.
January 2023 Updated the AD9833 VFO code to use a 12F1840.
December 2022 Added rant about todays useless (internet) search engines.
November 2022 NEW Project An AD9833 Based Simple VFO. FT101ZD VFO project updated.
October 2022 A replacement internal DDS VFO for FT101Z/ZD rigs. Because the worlds postage system has gone totally bonkers and it is not possible to send a small pcb anywhere except at extreme cost, I am slowly making available the option to purchase pcb's from Pcbway. First up is the Simple DDS VFO 2017 project pcb. Others will be added over time. Noise Canceller kits available again- see Noise Canceller page.
Privacy Policy uploaded. GPDR and all that stuff In accordance with various bits of legislation around the world, either currently in force, about to come into force or proposed, you will now find that annoying "We use cookies" notice at the top of this website. The full Privacy Policy is available at the Privacy Policy link in the footer at the bottom of the page. (If you don't know what GPDR is, Google it. Real scary shit for ANYBODY with a web presence.)
Simple Sweeper
A Simple DDS based sweeper using an 8-pin PIC.
This is a very basic, no frills and simple sweep unit using an AD9850 (or AD9851) module and a 8 pin PIC. It came about from a request by a user of my Simple DDS VFO. There are no bells and whistles, user controls (other than an on/off switch) or trigger output and the sweep frequency (beginning and end) needs hard programming in. The step frequency is hard coded at 5kHz in the demo software below (which sweeps 50kHz to 30MHz), but could be reduced to a smaller value if the beginning and end frequency are reduced to a smaller range. It takes approximately 1 second to sweep the range from 50kHz to 30MHz at 5kHz steps. This will increase to about 3 seconds if the step size is reduced to 1kHz. To get this rate of sweep, a much faster PIC than the 12F629 is required, so a 12F1840 running at 32MHz has been used. There are 3 pins unused currently, two of which can be either input or output and one that is an input only. With appropriate programming, extra features could be added using these pins. No option to calibrate the DDS frequency is available in the software, although it could be added if deemd necessary or, by trial and error, the Ref_osc values can be manually adjusted. Go at it, experiment with the software and see how much more you can get out of such a simple project, there is a LOT of code space remaining. If you do add significant features or improve on the software, please let me know so it can be added to this page.
Software
The demo software provided below is very basic and no attempt to optimise it (except where necessary) to use the expanded range of commands available in the enhanced range of PIC's has been made (including the use of LATA instead of PORTA for writes to the port). You will need to input the values of and recompile the software for your required start, stop and step size frequencies: Limit - The upper limit frequency you want the Simple Sweeper to reach. Starts at line 90. Limit_Low - The lower limit frequency you want the Simple Sweeper to start at. Starts at line 98. Step size - The size of the frequency steps. You will find this at line 278 in the asm file.
Downloads
These files are provided free for personal use ONLY. I retain copyright on all works published on this website (unless otherwise specified). These files, or any derivative of them, may NOT be used in any commercial or profit making enterprise of any kind. I no longer make pcb files available because of copyright infringement.
(Right click and 'Save as..' or what ever is required by your browser) simple_sweep.asm The ASM file for the Sweeper. It is set to AD9850 by default. Instructions in the file to change it to AD9851. Default range 50kHz - 30MHz, 5kHz steps. simple_sweep.hex AD9850 hex file.
