/**
* Commands
* Rxxxxxx: Read word in from a given 22bit hex address
* Wxxxxxx:xxxx: Write a hex word to a given 22bit hex address
* BLOW: Set chip select + chip enable to read from first bank (default)
* BHI: Set chip select + chip enable to read from second bank
* ACK: Acknowledge byte transfer, after dumper sends data it awaits for an ACK for 18ms
*
* Dxxxx:ssssss Dumps attached cartridge to sd-card with filename x and size s
* Fxxxx: Flashes rom from sd-card to cartridge
*
* Terminator character: %
**/