28C256 DATASHEET PDF

28C256 DATASHEET PDF

28C datasheet, 28C pdf, 28C data sheet, datasheet, data sheet, pdf, Atmel, K 32K x 8 Paged CMOS E2PROM. 28C Microchip. K (32K x 8) CMOS Electrically Erasable PROM. PIN CONFIGURATION. Top View. A 1 A7. A A *NC. Vcc. WE. [1]. A2. 5 WE. A dimensions section on page 14 of this data sheet. ORDERING INFORMATION. PLCC−32 . 28C− 28C− Units. Min. Max. Min. Max. tRC.

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Fast Read Access Time – ns. Automatic Satasheet Write Operation. Fast Write Cycle Times. Page Write Cycle Time: Hardware and Software Data Protection. Its K of memory is organized as 32, words by 8 bits. Manufac- tured with Atmel’s advanced nonvolatile CMOS technology, the device offers access times to ns with power dissipation of just mW.

When the device is deselected, the CMOS standby current is less than The device contains a byte page register to allow writ- ing of up to bytes simultaneously. During a write cycle, the addresses and 1 to bytes of data are internally latched, freeing the address and data bus for other opera- tions.

Following the initiation of a write cycle, the device will automatically write the latched data using an internal control timer. Once the datashset of a write cycle has been detected a new datahseet for a read or write can begin. Atmel’s 28C has additional features to ensure high quality and manufacturability.

The device utilizes internal error correction for extended endurance and improved data retention characteristics. An optional software data protection mechanism is available to guard against inad- vertent writes.

The device also includes an extra bytes of E. PROM for device identification or tracking.

All Output Voltages with Respect to Ground Stresses beyond those listed under “Absolute Maxi. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indi- cated in the operational sections of this specification is not implied.

Exposure to absolute maximum rating conditions for extended periods may affect device reliability. When CE and OE are low and WE is high, the data stored at the memory location determined by the address pins is asserted on the outputs.

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The outputs are put in the high impedance state when either CE datashee OE is high. ddatasheet

28C 데이터시트(PDF) – ATMEL Corporation

This dual- line control gives designers flexibility in preventing bus contention in their system. The address is latched on the falling edge of CE or WE, whichever occurs last. The data is latched by the first rising edge of CE or WE.

Once a byte write has been started it will automatically time itself to completion. Once a programming operation has been initiated and for the duration of t.

28C256 – 28C256 256K 250ns Parallel EEPROM Datasheet

The page write operation of the Daatasheet allows 1 to bytes of data to be written dqtasheet the device during a single internal programming period.

A page write operation is initiated in the same manner as a byte write; the first byte written can then be followed by 1 to 63 addi- tional bytes. Each successive byte must be written within All bytes dur- ing a page write operation must reside on the same page as defined by the state of the A6 – A14 inputs.

For each WE high to low transition during the page write operation, Datashheet – A14 must be the same. The A0 to A5 inputs are used to specify which bytes within the page are to be written.

The bytes may be loaded in any order and may be altered within the same load period. Only bytes which are specified for writing will be written; unnecessary cycling of other bytes within the page does not occur.

Once the write cycle has been completed, true data is valid on all outputs, and the next write cycle may begin. DATA Polling may begin at anytime during the write cycle. Reading the toggle bit may begin at any time during the write cycle. If precautions are not dagasheet, inad- vertent writes may occur during transitions of the host sys- tem power supply.

Atmel has incorporated both hardware and software features that will protect the memory 28c25 inadvertent writes. Hardware datasheer protect against inadvertent writes to the AT28C in the follow- ing ways: A software controlled data protection feature has been implemented on the AT28C When enabled, the software data protection SDPwill prevent inadvertent writes. 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 Algorithm.

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After writing the 3-byte command sequence and after t. It should 282c56 noted, that once protected the host may still perform a byte or page write to the AT28C This is done by pre- ceding the data to be written by the same 3-byte command sequence used to enable SDP. Once set, SDP 28c2556 remain active unless the disable com- mand sequence is issued. All command se- quences must conform to the page write timing specifica- tions.

The data in the enable and disable command se- quences is not written to the device and the memory ad- dresses 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 with- out 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. X can be V. Refer to AC Programming Waveforms.

PROM memory are available to the user for device. By raising A9 to 12V. The entire device can be erased using a 6-byte software code. Please see Soft- ware Chip Erase application note for details. Address to Output Delay. CE to Output Delay.

OE to Output Delay. CE may be delayed up to t. OE may be delayed up to t. Input Test Waveforms and Measurement Level. Search field Part name Part description.