at45db021a ATMEL Corporation, at45db021a Datasheet - Page 15

• Manufacturer Part Number: at45db021a
• Description: 2-megabit 2.7-volt Only Serial Dataflash
• Manufacturer: ATMEL Corporation

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
SO
CS
SI
Each transition represents
8 bits and 8 clock cycles
CMD
SO
CS
SI
MAIN MEMORY
PAGE (264 BYTES)
BUFFER 1 (264 BYTES)
r r r r r, PA9-7
BUFFER 1
BUFFER 1
SO
CS
PAGE TO
SI
READ
CMD
PA6-0, BA8
CMD
X
FLASH MEMORY ARRAY
BA7-0
X···X, BFA8
r r r r r, PA9-7
I/O INTERFACE
SO
X
MAIN MEMORY
PAGE READ
Starts reading page data into buffer
BFA7-0
PA6-0, X
X
BUFFER 2 (264 BYTES)
X
X
X
n
MAIN MEMORY
PAGE TO
BUFFER 2
BUFFER 2
READ
n+1
X
n = 1st byte read
n+1 = 2nd byte read
n
n+1
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