ADF435x PIC

The incredibly flexible ADF4351 VCO/PLL chip with a few external components forms a very wide range high stability signal source with a clean output which is programmable from 35 MHz to 4.4 GHz. Such a device would have been unthinkable 10 years and is ideal for user in the ATVers shack as a test signal generator or a local oscillator source for all bands up to 5.6 GHz.

Note: As well as the desired frequency, the boards have a high harmonic content and depending on the application will need filtering on the output.

Ready built and tested boards are readily available from a number of Far Eastern sources on eBay for around £20

In CQ-TV253, Ron G7DOE described two PIC-based controllers for Chinese ADF435x boards to provide a configurable DATV local oscillator. The PIC holds four frequencies selectable by two small switches, extendible to eight frequencies from three switches if required. It is easy to change the C source code for any appropriate frequencies and the circuit is very simple. There is also a ultra simple controller design for a set and forget a single frequency which can also be used as a microwave band local Oscillator.

PCB

A blank PCB for this project is now available from the BATC shop.

File:adf435x.zip contains the Gerber files for the V2 pcb. These are bundled to suit OSH Park's naming conventions but should also suit various Chinese fabricators.

Software

Software used was: MPLABX\v3.51 downloaded free from Microchip. When compiled the package directly programs the PIC using Pickit 3.

The compiler is XC8 which is also downloaded from the same site and integrates with MPLABX IDE.

http://www.microchip.com/mplab/mplab-x-ide

Thanks to Steve M0SKM for articulating this first when the question popped up.

Source files

File:source.zip contains four C source files:

• fatcontrol.c is the PIC12LF1552 controller offering a choice of 4 frequencies
• fat8sw.c is the PIC12LF1552 controller offering a choice of 8 frequencies
• thincontrol.c is the PIC12F629 controller offering a single frequency
• thin1552.c is the PIC12LF1552 controller offering a single frequency

Note that you cannot program a 12F629 on my 3v board; it needs 5v to progam but will run happily at 3v.

Code Compilation and PIC Programming Guide

Following a request for help I have written a guide in .pdf format.

When Ron Mount wrote the article for CQ-TV he supplied four files coded in C; and these can be edited in plain text reasonably easy. The stumbling block it seems has been compiling and writing the code to a PIC. Hopefully my guide will encourage others to build these very useful oscillators.

When I first tackled this project I looked around for software and learned it from scratch. Others will undoubtedly find alternative methods but this way worked for me. Thanks also to Claudio I2NDT who test ran the guide successfully.

The guide can be downloaded here File:7-band local oscillator.pdf.