Veronica PLL model is quite popular among the experimenter FM Broadcast, with pretty good audio quality and the rf signal is so clean, very little spurious signal / her spleteran. But as we know this model PLL still use the "dip switches" to "setting" the working frequency of the PLL. We must always refer to the manual or the table position dip switches for each desired frequency.
For that reason perhaps, by adding a series of programmable digital switches that can replace the role of the dip switches, it is rather easy and not too much trouble. Because only by seeing the display "display", position switches will be in accordance with the program for the desired frequency as when we use manual dipswitch.
One of the requirements that must be met by a programmable switch is able to cover from 88 MHz - 108 MHz, while also be able to save the last state of the program even if power is turned off.
To realize them, for the sake of practicality and of course cheap, used microcontroller, in this project using microcontroller family of Atmel are quite popular and many on the market.
To use the I2C memory storage, (also from Atmel) with IC memory we do not need to reset the working frequency, when the PLL been turned off.
By using the software programs are sufficient IC, this circuit can be programmed from the frequency of 88-108 MHz, to change the frequency to stay pressing the SET / RESET button followed by pressing the UP or DOWN. After achieving the desired frequency, then press the SAVE lives. Position switch / display will be the last time we had "SAVE".