The code is simple and gets the job done. I did a few easy changes:
- corrected the "MHz" label (was "Mhz")
- delayed the store timing of the latest tuned frequency (2s, now 20s, not to stress the uC EEPROM)
- added a visual feedback whether the latest frequency has been stored or not
To my surprise the whole circuit draws about 165 mA: that's a lot of current! That's 0.8 W or power consumption. Even if the AD9850 DDS offers a huge frequency agility in an HF RX/TX, that's at the expense of current consumption. I will not give away my QRP frequency XTALs just yet!