參數(shù)資料
型號: NAND256W3A2BV1T
廠商: STMICROELECTRONICS
元件分類: PROM
英文描述: 32M X 8 FLASH 3V PROM, 35 ns, PDSO48
封裝: 12 X 17 MM, 0.65 MM HEIGHT, PLASTIC, USOP-48
文件頁數(shù): 25/57頁
文件大?。?/td> 916K
代理商: NAND256W3A2BV1T
31/57
NAND128-A, NAND256-A, NAND512-A, NAND01G-A
Figure 21. Garbage Collection
Garbage Collection
When a data page needs to be modified, it is faster
to write to the first available page, and the previous
page is marked as invalid. After several updates it
is necessary to remove invalid pages to free some
memory space.
To free this memory space and allow further pro-
gram operations it is recommended to implement
a Garbage Collection algorithm. In a Garbage Col-
lection software the valid pages are copied into a
free area and the block containing the invalid pag-
es is erased (see Figure 21.).
Wear-leveling Algorithm
For write-intensive applications, it is recommend-
ed to implement a Wear-leveling Algorithm to
monitor and spread the number of write cycles per
block.
In memories that do not use a Wear-Leveling Algo-
rithm not all blocks get used at the same rate.
Blocks with long-lived data do not endure as many
write cycles as the blocks with frequently-changed
data.
The Wear-leveling Algorithm ensures that equal
use is made of all the available write cycles for
each block. There are two wear-leveling levels:
First Level Wear-leveling, new data is
programmed to the free blocks that have had
the fewest write cycles
Second Level Wear-leveling, long-lived data is
copied to another block so that the original
block can be used for more frequently-
changed data.
The Second Level Wear-leveling is triggered when
the difference between the maximum and the min-
imum number of write cycles per block reaches a
specific threshold.
Error Correction Code
An Error Correction Code (ECC) can be imple-
mented in the Nand Flash memories to identify
and correct errors in the data.
For every 2048 bits in the device it is recommend-
ed to implement 22 bits of ECC (16 bits for line par-
ity plus 6 bits for column parity).
An ECC model is available in VHDL or Verilog.
Contact the nearest ST Microelectronics sales of-
fice for more details.
Figure 22. Error Detection
Valid
Page
Invalid
Page
Free
Page
(Erased)
Old Area
AI07599B
New Area (After GC)
New ECC generated
during read
XOR previous ECC
with new ECC
All results
= zero?
22 bit data = 0
YES
11 bit data = 1
NO
1 bit data = 1
Correctable
Error
ECC Error
No Error
ai08332
>1 bit
= zero?
YES
NO
相關(guān)PDF資料
PDF描述
NAND01GR4A2BN1T 64M X 16 FLASH 1.8V PROM, 35 ns, PDSO48
NAND256W3A2CZA1E 32M X 8 FLASH 3V PROM, 35 ns, PBGA55
NAND01GR4A2AZB6 64M X 16 FLASH 1.8V PROM, 35 ns, PBGA63
NAND01GW3B2CN1E 128M X 8 FLASH 3V PROM, 25000 ns, PDSO48
NAND04GR3B3AN6 512M X 8 FLASH 1.8V PROM, 35 ns, PDSO48
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
NAND256W3A2BWFD 制造商:Micron Technology Inc 功能描述:NAND 制造商:Micron Technology Inc 功能描述:NAND - Gel-pak, waffle pack, wafer, diced wafer on film
NAND256W3A2BZA6 制造商:STMicroelectronics 功能描述:
NAND256W3A2BZA6E 功能描述:閃存 NAND MEDIA FLASH RoHS:否 制造商:ON Semiconductor 數(shù)據(jù)總線寬度:1 bit 存儲類型:Flash 存儲容量:2 MB 結(jié)構(gòu):256 K x 8 定時類型: 接口類型:SPI 訪問時間: 電源電壓-最大:3.6 V 電源電壓-最小:2.3 V 最大工作電流:15 mA 工作溫度:- 40 C to + 85 C 安裝風格:SMD/SMT 封裝 / 箱體: 封裝:Reel
NAND256W3A2BZA6F 制造商:Micron Technology Inc 功能描述:SLC NAND Flash Parallel 3V/3.3V 256Mbit 32M x 8bit 12us 55-Pin VFBGA T/R 制造商:Micron Technology Inc 功能描述:FLASH PARALLEL 3V/3.3V 256MBIT 32MX8 12US 55VFBGA - Tape and Reel
NAND256W4A0AN6E 功能描述:閃存 NAND & S.MEDIA FLASH RoHS:否 制造商:ON Semiconductor 數(shù)據(jù)總線寬度:1 bit 存儲類型:Flash 存儲容量:2 MB 結(jié)構(gòu):256 K x 8 定時類型: 接口類型:SPI 訪問時間: 電源電壓-最大:3.6 V 電源電壓-最小:2.3 V 最大工作電流:15 mA 工作溫度:- 40 C to + 85 C 安裝風格:SMD/SMT 封裝 / 箱體: 封裝:Reel