Owner's manual

17
AT45DB021B
1937F–DFLSH–10/02
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
rrrr r, PA9-7
PA6-0, BA8
BA7-0 X
XXX
CS
n n+1
SO
SI
CMD
rrrr r, 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 c
y
cles
n=1stbyteread
n+1 = 2nd byte read