参数资料
型号: AT45DB080-TI
厂商: ATMEL CORP
元件分类: DRAM
英文描述: 8-Megabit 2.7-volt Only Sequential Access Parallel I/O DataFlash
中文描述: 8M X 1 FLASH 2.7V PROM, 180 ns, PDSO32
封装: PLASTIC, MO-142BD, TSOP-32
文件页数: 4/18页
文件大小: 158K
代理商: AT45DB080-TI
AT45DB080
4
AUTO PAGE REWRITE:
This mode is only needed if multi-
ple bytes within a page or multiple pages of data are modi-
fied in a random fashion. This mode is a combination of two
operations: Main Memory Page to Buffer Transfer and
Buffer to Main Memory Page Program with Built-In Erase.
A page of data is first transferred from the main memory to
buffer 1 or buffer 2, and then the same data (from buffer 1
or buffer 2) is programmed back into its original page of
main memory. A 1-byte opcode, 58H for buffer 1 or 59H for
buffer 2, is followed by the three address bytes comprised
of three reserved bits, 12 address bits (PA11-PA0) that
specify the page in main memory to be rewritten, and nine
additional don't care bits. When a low to high transition
occurs on the CS pin, the part will first transfer data from
the page in main memory to a buffer and then program the
data from the buffer back into same page of main memory.
The operation is internally self-timed and should take place
in a maximum time of t
EP
. During this time, the status regis-
ter will indicate that the part is busy.
If the main memory is programmed or reprogrammed
sequentially page by page, then the programming algo-
rithm shown in Figure 1 is recommended. Otherwise, if
multiple bytes in a page or several pages are programmed
randomly in the main memory, then the programming algo-
rithm shown in Figure 2 is recommended.
STATUS REGISTER:
The status register can be used to
determine the device’s ready/busy status, the result of a
Main Memory Page to Buffer Compare operation, or the
device density. To read the status register, an opcode of
57H must be loaded into the device. After the opcode is
clocked in, the 1-byte status register will be clocked out on
the output pins during the next clock cycle. The five most-
significant bits of the status register will contain device
information, while the remaining three least-significant bits
Status Register Format
are reserved for future use and will have undefined values.
After the one byte of the status register has been clocked
out, the sequence will repeat itself (as long as CS remains
low and CLK is being toggled). The data in the status regis-
ter is constantly updated, so each repeating sequence will
output new data.
Ready/busy status is indicated using bit 7 of the status reg-
ister. If bit 7 is a 1, then the device is not busy and is ready
to accept the next command. If bit 7 is a 0, then the device
is in a busy state. The user can continuously poll bit 7 of the
status register on I/O7 by stopping CLK once bit 7 has
been output on I/O7. The status of bit 7 will continue to be
output on the I/O7 pin, and once the device is no longer
busy, the state of I/O7 will change from 0 to 1. There are six
operations which can cause the device to be in a busy
state: Main Memory Page to Buffer Transfer, Main Memory
Page to Buffer Compare, Buffer to Main Memory Page Pro-
gram with Built-In Erase, Buffer to Main Memory Page Pro-
gram without Built-In Erase, Main Memory Page Program,
and Auto Page Rewrite.
The result of the most recent Main Memory Page to Buffer
Compare operation is indicated using bit 6 of the status
register. If bit 6 is a 0, then the data in the main memory
page matches the data in the buffer. If bit 6 is a 1, then at
least one bit of the data in the main memory page does not
match the data in the buffer.
The device density is indicated using bits 5, 4, and 3 of the
status register. For the AT45DB080, the three bits are 1, 0,
and 0. The decimal value of these three binary bits does
not equate to the device density; the three bits represent a
combinational code relating to differing densities of Serial
DataFlash devices, allowing a total of eight different density
configurations.
Read/Program Mode Summary
The modes listed above can be separated into two groups
— modes which make use of the flash memory array
(Group A) and modes which do not make use of the flash
memory array (Group B).
Group A modes consist of:
1.
Main memory page read
2.
Main memory page to buffer 1 (or 2) transfer
3.
Main memory page to buffer 1 (or 2) compare
4.
Buffer 1 (or 2) to main memory page program with
built-in erase
5.
Buffer 1 (or 2) to main memory page program with-
out built-in erase
6.
7.
Group B modes consist of:
1.
Buffer 1 (or 2) read
2.
Buffer 1 (or 2) write
3.
Status read
If a Group A mode is in progress (not fully completed) then
another mode in Group A should not be started. However,
during this time in which a Group A mode is in progress,
modes in Group B can be started.
This gives the Serial DataFlash the ability to virtually
accommodate a continuous data stream. While data is
being programmed into main memory from buffer 1, data
Main memory page program
Auto page rewrite
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
RDY/BUSY
COMP
1
0
0
X
X
X
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AT45DB081B-CNU 8-megabit 2.5-volt Only or 2.7-volt Only DataFlash
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