Big Kahuna Arduino Wiring
The wiring of the Arduino, Si5351 and the 320X240 Color TFT is not complex but is more than hooking up two wires. The wiring information is being presented as a wire listing of what goes to what. That siad there is detail contained in the Sketch comments that like wise give direction on the wiring. These two docuemnst are necessary to successfully wire up the circuitry.
In other displays it is possible to connect directly to the display right from the Arduino. However this is not the case if you are using a 5 VDC type Arduino. The signal levels for the 320X240 require 3.3 Volts and thus you must use a level shifter which is found in a CD4050. Essentially 5 Volt signals coming from the Nano look like 3.3 volts after passing through the CD4050.
The Si5351 uses the I2C buss and so there are four wires from the Nano: A4 = SDA , A5 = SCL plus 5 VDC and Ground. The encoder needs 4 wires Pins 2 & 3 plus Ground and if you use the internal push button on the encoder then pin A3 and Ground is also connected. The encoder and push button can share a common ground 4 wires total.
The 320X240 Display takes advantage of the Serial Peripheral Interface (SPI) using the 6 pin ICSP connector (In Circuit Serial Programming Connector). Be sure to check the pin out of this top mounted connector --most follow a standard but some do not. The last thing you want to do is smoke your Nano!
This is to get you started and photographs of my build will be added at a later date.