And the same for 5pF parasitic capacitance between the pins and 200ohm (no resistor), 10k, 200k serial resistor. It seems the 200k does not create a glitch in the oscillation (in this simulation).
Disclaimer: simple simulation only, with different parts as included within 1284p. For demo purposes only. No warranties of any kind.
PS: The very bottom picture is probably the most realistic simulation out of all above- with 4049 inverter simulating the 1284p oscillator with more power (full swing), and 10pF capacitance between the RX and XTAL1 pins. The oscillator period changed from 127.1ns to 135.4ns after the Rx' rising edge (thus the frequency)..
