AT45D021

9

Write Operations

The following block diagram and waveforms illustrate the various write sequences available.

Main Memory Page Program through Buffers

Buffer Write

Buffer to Main Memory Page Program

(Data from Buffer Programmed into Flash Page)

FLASH MEMORY ARRAY

PAGE (264 BYTES)

BUFFER 2 (264 BYTES)

BUFFER 1 (264 BYTES)

I/O INTERFACE

SI

BUFFER 1 TO

MAIN MEMORY

PAGE PROGRAM

MAIN MEMORY

PAGE PROGRAM

THROUGH BUFFER 2

BUFFER 2 TO

MAIN MEMORY

PAGE PROGRAM

MAIN MEMORY PAGE

PROGRAM THROUGH

BUFFER 1

BUFFER 1

WRITE

BUFFER 2

WRITE

SI

CMD

n

n+1

Last Byte

· Completes writing into selected buffer

· Starts self-timed erase/program operation

CS

rrrrr, PA9-7

PA6-0, BFA8

BFA7-0

SI

CMD

X

X···X, BFA8

BFA7-0

n

n+1

Last Byte

· Completes writing into selected buffer

CS

SI

CMD

rrrrr, PA9-7

PA6-0, X

CS

Starts self-timed erase/program operation

X

Each transition represents

8 bits and 8 clock cycles

n = 1st byte read

n+1 = 2nd byte read