AT45D021

10

Read Operations

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

Main Memory Page Read

Main Memory Page to Buffer Transfer (Data from Flash Page Read into Buffer)

Buffer Read

FLASH MEMORY ARRAY

PAGE (264 BYTES)

BUFFER 2 (264 BYTES)

BUFFER 1 (264 BYTES)

I/O INTERFACE

MAIN MEMORY

PAGE TO

BUFFER 1

MAIN MEMORY

PAGE TO

BUFFER 2

MAIN MEMORY

PAGE READ

BUFFER 1

READ

BUFFER 2

READ

SO

SI

CMD

rrrrr, PA9-7

PA6-0, BA8

BA7-0

X

X

X

X

CS

n

n+1

SO

SI

CMD

rrrrr, PA9-7

PA6-0, X

X

Starts reading page data into buffer

CS

SO

SI

CMD

X

X···X, BFA8

BFA7-0

CS

n

n+1

SO

X

Each transition represents

8 bits and 8 clock cycles

n = 1st byte written

n+1 = 2nd byte written