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.