AT45DB321 ATMEL Corporation, AT45DB321 Datasheet - Page 18

• Manufacturer Part Number: AT45DB321
• Description: 32-Megabit 2.7-volt Only Serial DataFlash
• Manufacturer: ATMEL Corporation

Figure 2. Algorithm for Randomly Modifying Data
Notes:
Sector Addressing
18
PA12
0
0
0
0
1
1
1
1
•
•
•
1. To preserve data integrity, each page of a DataFlash sector must be updated/rewritten at least once within every 10,000
2. A Page Address Pointer must be maintained to indicate which page is to be rewritten. The Auto Page Rewrite command
3. Other algorithms can be used to rewrite portions of the Flash array. Low power applications may choose to wait until 10,000
cumulative page erase/program operations within that sector.
must use the address specified by the Page Address Pointer.
cumulative page erase/program operations have accumulated before rewriting all pages of the sector. See application note
AN-4 (“Using Atmel’s Serial DataFlash”) for more details.
PA11
0
0
0
0
1
1
1
1
•
•
•
AT45DB321
PA10
MAIN MEMORY PAGE PROGRAM
0
0
0
1
0
0
1
1
•
•
•
(82H, 85H)
PA9
0
0
1
0
0
1
0
1
•
•
•
to BUFFER TRANSFER
ADDRESS POINTER
MAIN MEMORY PAGE
PA8
Auto Page Rewrite
INCREMENT PAGE
X
X
X
X
X
X
X
0
•
•
•
(53H, 55H)
(58H, 59H)
START
END
provide address of
page to modify
PA7
X
X
X
X
X
X
X
0
•
•
•
MEMORY PAGE PROGRAM
(2)
(2)
BUFFER to MAIN
BUFFER WRITE
(84H, 87H)
(83H, 86H)
PA6
0
X
X
X
X
X
X
X
•
•
•
If planning to modify multiple
bytes currently stored within
a page of the Flash array
PA5
X
X
X
X
X
X
X
0
•
•
•
PA4
X
X
X
X
X
X
X
0
•
•
•
PA3
X
X
X
X
X
X
X
0
•
•
•
Sector
13
14
15
16
0
1
2
3
•
•
•