Tak - Refer to image. I simply used jumpers to connect the onboard 16Mhz resonator.
And a lot of great info. Ill surely look into that and post back. Much appreciated!
I can't follow the connections from the photo, there are just too many long looping jumpers everywhere.
You've got an Uno with no MCU and then two breadboards, one with a 328 and another with 1284.
Are you trying to share the Uno 16mhz crystal with both of these? If so then you can't just pick up both sides on the crystal to both XTAL pins on each chip. On one you drive the crystal normally and on the other just link the crystal output to XTAL in of 2nd chip I believe.
Also bear in mind that the XTAL pins are the opposite way round on 1284 vs 328. On the 328 it's the low impedance pin adjacent signal pin. On the 1284 it's the high impedance XTAL pin adjacent The RX0 signal pin. This is one reason we had issues with serial uploads on 1284 without adequate ground rings or full swing oscillator; the high z XTAL pin on 1284 seemed to susceptible to capacitively induced interference from the adjacent RX0 pin.