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参数资料
| 型号： | W28V400 |
| 英文描述： | FLASH |
| 中文描述： | 闪光 |
| 文件页数： | 8/48页 |
| 文件大小： | 427K |
| 代理商： | W28V400 |
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W28V400B/T
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7. PRINCIPLES OF OPERATION
The W28V400B/T SmartVoltage Flash memory includes an on-chip WSM to manage block erase, full
chip erase, word/byte write and lock-bit configuration functions. It allows for 100 percent TTL-level
control inputs, fixed power supplies during block erase, full chip erase, word/byte write and lock-bit
configuration, and minimal processor overhead with RAM-like interface timings.
After initial device power-up or return from reset mode (see Bus Operations section), the device
defaults to read array mode. Manipulation of external memory control pins allow array read, standby
and output disable operations.
Status register and identifier codes can be accessed through the CUI independent of the V
PP
voltage.
High voltage on V
PP
enables successful block erase, full chip erase, word/byte writing. All functions
associated with altering memory contents (block erase, full chip erase, word/byte write, status and
identifier codes) are accessed via the CUI and verified through the status register.
Commands are written using standard microprocessor write timings. The CUI contents serve as input
to the WSM, which controls the block erase, full chip erase, word/byte write and lock-bit configuration.
The internal algorithms are regulated by the WSM, including pulse repetition, internal verification and
margining of data. Addresses and data are internally latched during write cycles. Writing the
appropriate command outputs array data, accesses the identifier codes, or outputs status register
data.
Interface software that initiates and polls progress of block erase, full chip erase, word/byte write and
lock-bit configuration can be stored in any block. This code is copied to and executed from system
RAM during flash memory updates. After successful completion, reads are again possible via the
Read Array command. Block erase suspend allows system software to suspend a block erase to
read/write data from/to blocks other than that which is suspend. Word/byte write suspend allows
system software to suspend a word/byte write to read data from any other flash memory array
location.
Data Protection
Depending on the application, the system designer may choose to make the V
PP
power supply
switchable (available only when memory block erases or word/byte writes are required) or hardwired
to V
PPH1/2/3
. The device accommodates either design practice and encourages optimization of the
processor-memory interface.
When V
PP
≤
V
PPLK
, memory contents cannot be altered. The CUI, with two-step block erase or
word/byte write command sequences, provides protection from unwanted operations even when high
voltage is applied to V
PP
. All write functions are disabled when V
DD
is below the write lockout voltage
V
LKO
or when #RESET is at V
IL
. The device’s boot blocks locking capability for #WP provides
additional protection from inadvertent code or data alteration by block erase and word/byte write
operations.
Refer to Table 6 for write protection alternatives.
相关PDF资料 |
PDF描述 |
|---|---|
| W29C020C12BN | EEPROM|FLASH|256KX8|CMOS|DIP|32PIN|PLASTIC |
| W29C020C90BN | x8 Flash EEPROM |
| W29C040-12 | EEPROM|FLASH|512KX8|CMOS|DIP|32PIN|PLASTIC |
| W29C040-12N | x8 Flash EEPROM |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| W28V400B | 制造商:WINBOND 制造商全称:Winbond 功能描述:4M(512K x 8/256K x 16) SMARTVOLTAGE FLASH MEMORY |
| W28V400BT85C | 制造商:WINBOND 制造商全称:Winbond 功能描述:4M(512K x 8/256K x 16) SMARTVOLTAGE FLASH MEMORY |
| W28V400T | 制造商:WINBOND 制造商全称:Winbond 功能描述:4M(512K x 8/256K x 16) SMARTVOLTAGE FLASH MEMORY |
| W28V400TT85C | 制造商:WINBOND 制造商全称:Winbond 功能描述:4M(512K x 8/256K x 16) SMARTVOLTAGE FLASH MEMORY |
| W28WH | 制造商:ETERNA 功能描述:TRACKLIGHT, FLEXIBLE TRACK COUPLER |
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