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參數(shù)資料
| 型號： | NM29A080EM |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | PROM |
| 英文描述： | 4 Mbit Uniform Sector, Serial Flash Memory |
| 中文描述： | 8M X 1 FLASH 5V PROM, PDSO28 |
| 封裝： | 0.350 INCH, PLASTIC, SOIC-28 |
| 文件頁數(shù)： | 5/14頁 |
| 文件大小： | 218K |
| 代理商： | NM29A080EM |
Device Operation
(Continued)
BLOCK ERASE
The Block Erase sequence erases a specified block (4 kB)
of data. Flash memory devices require that a block be in an
erased state prior to writing to a memory cell. In this man-
ner, a block must be erased prior to the recording of any
messages or storage of any images.
TL/D/12475–7
FIGURE 4. Block Erase Sequence
Functional Description
ORGANIZATION
The NM29A040/080 are 4-Mbit and 8-Mbit devices respec-
tively organized as 128/256 blocks of 128 pages. A block is
the smallest unit that can be erased and is 4 kbytes in size.
Within a block are 16 rows of 8 pages, each row 256 bytes
long. Each page is 32 bytes long. Read and write operations
always operate on a page at a time.
TL/D/12475–8
FIGURE 5. Device Organization
Reading or writing data to the Serial Flash involves clocking
data into or out of the data register. The data register is a
32-byte wide shift register, equivalent in size to one page.
When shifting in a full page, writing to the array and then
reading out the same page, the first bit shifted in will be the
first bit shifted out. If for example only 5 bytes are shifted in,
written to the array and then the same page is read out, 27
bytes should be shifted out before the original 5 bytes will
be shifted out. See Note 4 in the notifications section for an
explanation of multiple page writes and masking.
TL/D/12475–9
FIGURE 6. Block Organization
WRITE ONCE BLOCK
The NM29A040 contains 127 blocks (blocks 0 thru block
126) which are fully accessible to the user for reading, writ-
ing and erasing. The final block, number 127, has been set
aslde as a write once block. The pages in this block may
only be written to once. Once the data is written, it may not
be erased. In this manner, block 127 may be used for stor-
ing system configuration information that cannot be lost.
The NM29A080 operates in a similar manner but has 253
blocks that are fully accessible. Block 254 contains the un-
usable block information although this block has 256 pages
as opposed to the standard 128 pages.
The last block is not accessible through the normal Read
and Write commands. Special commands for Read (D0H)
and Write (F0H) are used to perform the last block opera-
tions. An erase operation is not available or usable on the
last block.
DATA REGISTER
The data register is a 32-byte FIFO that is used to shift data
into or out of the device. When a write operation is per-
formed, all 32 bytes are written to the currently addressed
page. Refer to Note 4 for how to write less than 32 bytes to
a page.
The data register may be used as an on-chip holding area
for partial page data. For example, if data is acquired exter-
nally in 8-byte multiples, the data register can be used to
hold each 8-byte segment. After the 4th such data segment,
an entire page of data will have been accumulated, at which
point the write command mat be issued. No data may be
shifted into or out of the data register while the device is
busy.
READY/BUSY OUTPUT
When the Serial Flash device is selected with CS held low,
then the DO pin reflects the Ready/Busy state of the de-
vice. This is true at all times except when reading data out
of the device, as in the Get-Status command or the Data-
Shift-Out command. When the device is unselected, the DO
output is in a high impedance state.
http://www.national.com
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相關(guān)PDF資料 |
PDF描述 |
|---|---|
| NM29A080EV | 4 Mbit Uniform Sector, Serial Flash Memory |
| NM29A080M | 4 Mbit Uniform Sector, Serial Flash Memory |
| NM29A080V | 4 Mbit Uniform Sector, Serial Flash Memory |
| NM34C02EM8 | 2K-Bit Standard 2-Wire Bus Interface |
| NM34C02LEM8 | 2K-Bit Standard 2-Wire Bus Interface |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| NM29A080EV | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:4-Mbit/8-Mbit CMOS Serial FLASH E2PROM |
| NM29A080M | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:4-Mbit/8-Mbit CMOS Serial FLASH E2PROM |
| NM29A080V | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:4-Mbit/8-Mbit CMOS Serial FLASH E2PROM |
| NM29N16 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:16 MBit (2M x 8 Bit) CMOS NAND FLASH E2PROM |
| NM29N16ER | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:NAND Flash EEPROM |
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