depending on your clock speed need, you must expect EMI !
the faster the more you get :-)
I suggest as always to add good groundplane and good decoubling capacitors as near the cpu as possible,
and series resistors in the powersupply line.
just use zero ohm in the beginning, can later be changed to ferite beads or resistor like 10 ohm, depending on your current usage, this will filter EMI but also it will protect you from EMC !
do the same on all inputs and outputs, and on powersupply regulator and such,
those zero ohm footprints are almost for free, but they really help later,
you can disable stuff, measure current, or add filters.
