Block erase addressing – Rainbow Electronics AT45DB021B User Manual
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AT45DB021B
1937F–DFLSH–10/02
place in a maximum time of t
EP
. During this time, the status register will indicate that the
part is busy.
BUFFER TO MAIN MEMORY PAGE PROGRAM WITHOUT BUILT-IN ERASE: A previ-
ously erased page within main memory can be programmed with the contents of either
buffer 1 or buffer 2. To start the operation, an 8-bit opcode (88H for buffer 1 or 89H for
buffer 2) must be followed by the five reserved bits, 10 address bits (PA9 - PA0) that
specify the page in the main memory to be written, and nine additional don’t care bits.
When a low-to-high transition occurs on the CS pin, the part will program the data stored
in the buffer into the specified page in the main memory. It is necessary that the page in
main memory that is being programmed has been previously erased. The programming
of the page is internally self-timed and should take place in a maximum time of t
P
. Dur-
ing this time, the status register will indicate that the part is busy.
Successive page programming operations without doing a page erase are not recom-
mended. In other words, changing bytes within a page from a “1” to a “0” during multiple
page programming operations without erasing that page is not recommended.
PAGE ERASE: The optional Page Erase command can be used to individually erase
any page in the main memory array allowing the Buffer to Main Memory Page Program
without Built-in Erase command to be utilized at a later time. To perform a Page Erase,
an opcode of 81H must be loaded into the device, followed by five reserved bits, ten
address bits (PA9-PA0), and nine don’t care bits. The ten address bits are used to spec-
ify which page of the memory array is to be erased. When a low-to-high transition occurs
on the CS pin, the part will erase the selected page to 1s. The erase operation is inter-
nally self-timed and should take place in a maximum time of t
PE
. During this time, the
status register will indicate that the part is busy.
BLOCK ERASE: A block of eight pages can be erased at one time allowing the Buffer
to Main Memory Page Program without Built-in Erase command to be utilized to reduce
programming times when writing large amounts of data to the device. To perform a
Block Erase, an opcode of 50H must be loaded into the device, followed by five
reserved bits, seven address bits (PA9 -PA3), and 12 don’t care bits. The seven address
bits are used to specify which block of eight pages is to be erased. When a low-to-high
transition occurs on the CS pin, the part will erase the selected block of eight pages to
1s. The erase operation is internally self-timed and should take place in a maximum
time of t
BE
. During this time, the status register will indicate that the part is busy.
Block Erase Addressing
PA9
PA8
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
Block
0
0
0
0
0
0
0
X
X
X
0
0
0
0
0
0
0
1
X
X
X
1
0
0
0
0
0
1
0
X
X
X
2
0
0
0
0
0
1
1
X
X
X
3
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
1
1
1
1
1
0
0
X
X
X
124
1
1
1
1
1
0
1
X
X
X
125
1
1
1
1
1
1
0
X
X
X
126
1
1
1
1
1
1
1
X
X
X
127