The url link posting to google drive, lists lower the tri-band software using not the AD9850 DDS, but the silicon labs Si5351 adafruit dds board. With this application, both the vfo and bfo frequencies are created, the adafruit si5351 board connected to the Arduino uno via the i2c data network connection, as well as the display and the led indicator board using the i2c interface chip. As a result, the Arduino uno still has four interface pins that are available for future use, however as with the si5351 board, good power supply decoupling is needed, as the clicking noise is heard on the receivers speaker. From what I have managed to pick up from the Bitx 40 websites info, the clicking is solved by good supply filtering, I assume that the si5351 chip requires a good current source from the power supply while changing frequency. A solution may be thus to have a separate power supply source connection from it's own psu regulator chip with good supply line filtering to give the current demand during a frequency change of the vfo needs.
The vfo tuning dial with a optical rotary encoder as well as the mechanical switch connections are as before.
https://docs.google.com/document/d/19g_lEkBG_p40s4xYKX8PsEN_5bWFVqZN-bAl51EryCA/edit?usp=sharing