Can you elaborate on this?
A capacitor inline between an output pin and reset pin?
no. between both pins and ground. the point is cap holds low longer so the incomplete reset mentioned in app notes does not occur. i used .1mfd but dont think value matters much, probably anything from 100pf to 100mfd.
in fact the cap is probably not needed at all but willing to give atmel benefit of the doubt. both projects were mission critical so thought it better not to take a chance. the few times i did it for hobby use no cap was used and it still worked ok.
I want to remotely reset a mega2560
imo the 555 is overkill. a simple cap will do the same thing. you dont have to hold reset for milliseconds, only a few microseconds.
ive used remote reset to remotely program an esp8266 and avr combo but no cap required since esp and not avr was doing the reset. remote reset via rfm22b (si4432 prone to hang) did need a cap because the avr was resetting itself and the transceiver.