Truth Table/Functionality

Address Operations
arclk	ardin	arshft	Function
rising edge	0 or 1	1	Shifts value at `ardin` port to the address register.
rising edge	don't care	0	Increments the address stored in the address register by `1`.
falling edge	don't care	don't care	No change.
constant	don't care	don't care	No change.

Data Operations
drclk	drdin	drshft	drdout	Function
rising edge	0 or 1	1	MSB of data register	Shifts value at `drdin` port to the `data` register (LSB to MSB).
rising edge	don't care	0	MSB of data register	Loads data at the memory location that is pointed to in the address register value from the flash to the data register. The MSB is immediately seen on the `drdout` port.
falling edge	don't care	don't care	No change.	No change.
constant	don't care	don't care	No change.	No change.

Control Block Operations
program	erase	busy	Function
rising edge	don't care	0 -> 1	Programs the data contained in the data register to the address pointed to by the address register. The `busy` signal remains high until the program sequence is completed. The data and address registers should not be modified during this time.
don't care	rising edge	0 -> 1	The sector indicated by the MSB of the address register is erased.
rising edge	don't care	Already 1	Program instructions are ignored because the flash memory is already busy.
don't care	rising edge	Already 1	Erase instructions are ignored because the flash memory is already busy.
rising edge	rising edge	0 -> 1	The program instruction has a higher priority and is run. The `erase` signal is ignored.