(The VFO program is being revised and this page will soon be updated with full description, schematics and software for download.)
"VFO" is a simple VFO program that runs on the HC908 Daughtercard in the Digital Breadboard project (as chronicled in QRP Quarterly magazine) and serves as a general purpose, precise and accurate 0-to-30 MHz signal source. It assumes the hardware configuration of the Digital Breadboard is present and that the DDS Daughtercard (or equivalent) is in place. Note that this program does not yet conform to our standard use of the drivers and utilities modules used in other HC908 programs. It will soon.
Frequency selection is made by rotation of the shaft encoder. Shaft encoder frequency adjustment is speed-dependent, meaning that the incremental frequency changes are greater when the shaft encoder is turned faster. The frequency is displayed to the LCD. Band selection is made through a sub-menu, whereby a base frequency in each ham band is initially displayed. Up to 10 memory frequencies may be selected.