Hi Nick-
I have tried/did a little SPI communication with the MAX7221 chip before... but understanding this RFID is confusing for me.
(especially what registers/areas I can write to? which I cant?..etc..etc)
Also.. the link to the datasheet is in the first post.. (I zipped the .pdf's up and posted as attachment)
as far as str[] getting populated question..
I had posted an edit to the thread above saying I found it..
I didnt see it in the function you requested.. I had to follow the code a bit more to see another function that was called inside that function to see where (I posted the function above as well where it was found..etc)