AT26DF041-MU ATMEL [ATMEL Corporation], AT26DF041-MU Datasheet - Page 6

• Manufacturer Part Number: AT26DF041-MU
• Description: 4-MEGABIT 3.0-VOLT ONLY OR 2.7-VOLT ONLY SERIAL FIRMWARE DATAFLASH-R
• Manufacturer: ATMEL [ATMEL Corporation]

5.2.3
5.2.4
6
AT26DF041
Page Program with Auto-Erase
Page Erase
essary that the page in the main memory has been previously erased. The programming of
the page is internally self-timed and should take place in a maximum time of t
time, the status register will indicate that the device is busy.
Successive page programming operations without doing a page erase are not recommended.
In other words, changing bytes within a page from a “1” to a “0” during multiple page program-
ming operations without erasing that page is not recommended.
This operation functions similarly to the Page Program command except that the device will
automatically erase the addressed page in the main memory before it programs the page,
thereby eliminating the need to pre-erase the page or a block of memory. To initiate the oper-
ation, the 8-bit opcode of 82H must be clocked into the device followed by the 24-bit address
sequence (A23 - A0). Since the upper address limit of the device is 07FFFFh, the five most
significant bits (A23 - A19) are ignored. After all address bits are shifted in, the device will take
data from the SI pin and store it in the internal buffer. If the end of the buffer is reached, the
device will wrap around back to the beginning of the buffer. When there is a low-to-high transi-
tion on the CS pin, the part will first erase the selected page in main memory to all 1s and then
program the data stored in the buffer into the specified page in the main memory. Both the
erase and the programming of the page are internally self-timed and should take place in a
maximum of time t
Because of the single page erase granularity, care must be taken to preserve data integrity
within the memory array when using the Page Program with Auto-Erase command. If multiple
pages of data within a sector are modified in a random fashion numerous times while certain
pages within the same sector are never modified or modified infrequently, then the system
must ensure that each page within the sector is updated/rewritten, or “refreshed”, at least once
within every 10,000 cumulative page erase operations to that sector. For example, if the first
six pages of a sector are used to store static data and the remaining pages are used to store
changing data, then the first six pages of the sector must be “refreshed” within 10,000 cumula-
tive page erase operations to that sector. The pages used to store the changing data do not
need to be “refreshed” provided that the pages are updated sequentially or in such a fashion
that guarantees that each page is rewritten on a fairly even basis.
The optional Page Erase command can be used to individually erase any page in the main
memory array allowing the Page Program or Byte Program commands to be utilized at a later
time. To perform a Page Erase, an opcode of 81H must be loaded into the device followed by
the 24-bit address sequence. Address bits A23 - A19 are ignored since the upper address limit
of the device is 07FFFFh. In addition, address bits A7 - A0 are ignored since a full page of
data is being 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 internally self-timed and should take place in a
maximum time of t
Because of the single page erase granularity, care must be taken to preserve data integrity
within the memory array when using the Page Erase command. If multiple pages of data
within a sector are modified in a random fashion numerous times while certain pages within
the same sector are never modified or modified infrequently, then the system must ensure that
each page within the sector is updated/rewritten, or “refreshed”, at least once within every
10,000 cumulative page erase operations to that sector. For example, if the first six pages of a
sector are used to store static data and the remaining pages are used to store changing data,
EP
PE
. During this time, the status register will indicate that the part is busy.
. During this time, the status register will indicate that the part is busy.
3495B–DFLSH–8/05
P
. During this