参数资料
| 型号： | AT28C256F-15SC |
| 厂商： | Atmel |
| 文件页数： | 4/25页 |
| 文件大小： | 0K |
| 描述： | IC EEPROM 256KBIT 150NS 28SOIC |
| 标准包装： | 27 |
| 格式 - 存储器： | EEPROMs - 并行 |
| 存储器类型： | EEPROM |
| 存储容量： | 256K (32K x 8) |
| 速度： | 150ns |
| 接口： | 并联 |
| 电源电压： | 4.5 V ~ 5.5 V |
| 工作温度： | 0°C ~ 70°C |
| 封装/外壳： | 28-SOIC（0.295"，7.50mm 宽） |
| 供应商设备封装： | 28-SOIC W |
| 包装： | 管件 |
4.5
Toggle Bit
In addition to DATA Polling the AT28C256 provides another method for determining the end of a
write cycle. During the write operation, successive attempts to read data from the device will
result in I/O6 toggling between one and zero. Once the write has completed, I/O6 will stop tog-
gling and valid data will be read. Reading the toggle bit may begin at any time during the write
cycle.
4.6
4.6.1
4.6.2
4.7
4.8
4
Data Protection
If precautions are not taken, inadvertent writes may occur during transitions of the host system
power supply. Atmel has incorporated both hardware and software features that will protect the
memory against inadvertent writes.
Hardware Protection
Hardware features protect against inadvertent writes to the AT28C256 in the following ways: (a)
V CC sense – if V CC is below 3.8V (typical) the write function is inhibited; (b) V CC power-on delay –
once V CC has reached 3.8V the device will automatically time out 5 ms (typical) before allowing
a write; (c) write inhibit – holding any one of OE low, CE high or WE high inhibits write cycles;
and (d) noise filter – pulses of less than 15 ns (typical) on the WE or CE inputs will not initiate a
write cycle.
Software Data Protection
A software controlled data protection feature has been implemented on the AT28C256. When
enabled, the software data protection (SDP), will prevent inadvertent writes. The SDP feature
may be enabled or disabled by the user; the AT28C256 is shipped from Atmel with SDP
disabled.
SDP is enabled by the host system issuing a series of three write commands; three specific
bytes of data are written to three specific addresses (refer to “Software Data Protection” algo-
rithm). After writing the 3-byte command sequence and after t WC the entire AT28C256 will be
protected against inadvertent write operations. It should be noted, that once protected the host
may still perform a byte or page write to the AT28C256. This is done by preceding the data to be
written by the same 3-byte command sequence used to enable SDP.
Once set, SDP will remain active unless the disable command sequence is issued. Power transi-
tions do not disable SDP and SDP will protect the AT28C256 during power-up and power-down
conditions. All command sequences must conform to the page write timing specifications. The
data in the enable and disable command sequences is not written to the device and the memory
addresses used in the sequence may be written with data in either a byte or page write
operation.
After setting SDP, any attempt to write to the device without the 3-byte command sequence will
start the internal write timers. No data will be written to the device; however, for the duration of
t WC , read operations will effectively be polling operations.
Device Identification
An extra 64 bytes of EEPROM memory are available to the user for device identification. By rais-
ing A9 to 12V ± 0.5V and using address locations 7FC0H to 7FFFH the additional bytes may be
written to or read from in the same manner as the regular memory array.
Optional Chip Erase Mode
The entire device can be erased using a 6-byte software code. Please see “Software Chip
Erase” application note for details.
AT28C256
0006M–PEEPR–12/09
相关PDF资料 |
PDF描述 |
|---|---|
| AT28C256F-15PI | IC EEPROM 256KBIT 150NS 28DIP |
| 20-101-0525 | COMPUTER SINGLE-BOARD LP3500 FOX |
| AT28C256F-15PC | IC EEPROM 256KBIT 150NS 28DIP |
| AT28C256F-15JI | IC EEPROM 256KBIT 150NS 32PLCC |
| AT28C256F-15JC | IC EEPROM 256KBIT 150NS 32PLCC |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AT28C256F-15SI | 功能描述:电可擦除可编程只读存储器 256K FAST PROG SDP- 150NS IND TEMP RoHS:否 制造商:Atmel 存储容量:2 Kbit 组织:256 B x 8 数据保留:100 yr 最大时钟频率:1000 KHz 最大工作电流:6 uA 工作电源电压:1.7 V to 5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 |
| AT28C256F-15SU | 功能描述:电可擦除可编程只读存储器 256K FAST PROG SDP- 150NS IND TEMP RoHS:否 制造商:Atmel 存储容量:2 Kbit 组织:256 B x 8 数据保留:100 yr 最大时钟频率:1000 KHz 最大工作电流:6 uA 工作电源电压:1.7 V to 5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 |
| AT28C256F-15SU-T | 功能描述:150NS, SOIC, IND TEMP, GREEN 制造商:microchip technology 系列:- 包装:剪切带（CT） 零件状态:在售 存储器类型:非易失 存储器格式:EEPROM 技术:EEPROM 存储容量:256Kb （32K x 8） 写周期时间 - 字，页:3ms 访问时间:150ns 存储器接口:并联 电压 - 电源:4.5 V ~ 5.5 V 工作温度:-40°C ~ 85°C（TC） 安装类型:表面贴装 封装/外壳:28-SOIC（0.295"，7.50mm 宽） 供应商器件封装:28-SOIC 标准包装:1 |
| AT28C256F-15TC | 功能描述:电可擦除可编程只读存储器 256K FAST PROG SDP- 150NS COM TEMP RoHS:否 制造商:Atmel 存储容量:2 Kbit 组织:256 B x 8 数据保留:100 yr 最大时钟频率:1000 KHz 最大工作电流:6 uA 工作电源电压:1.7 V to 5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 |
| AT28C256F-15TI | 功能描述:电可擦除可编程只读存储器 256K FAST PROG SDP- 150NS IND TEMP RoHS:否 制造商:Atmel 存储容量:2 Kbit 组织:256 B x 8 数据保留:100 yr 最大时钟频率:1000 KHz 最大工作电流:6 uA 工作电源电压:1.7 V to 5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 |
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