BUT what pin is it using to tell the 84 to reset? mosi, clk, or miso? It has to use ONE of them to initiate the reset 
I was reading over the datasheets and it would seem the clock pin would actually be the trigger for turning ISP on? If that is the case then mosi and miso are both usable PWM streams, otherwise if it uses mosi pin then how would it send a reset command if a PWM stream was coming out of it?