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. . 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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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. Its K of memory is organized as 32, words by 8 bits. The bytes may be loaded in any order and may be altered within the same load period.
The entire device can be erased using a 6-byte software code. A software controlled data protection feature has been implemented on the AT28C Following the initiation of a write cycle, the device will automatically write the latched data using an internal control timer.
28C Datasheet pdf – K 32K x 8 Paged CMOS E2PROM – Atmel
OE may be delayed up to t. Once a programming operation has been initiated and for the duration of t. The A0 to A5 inputs are used to specify which bytes within the page are to be written.
The page write operation of the AT28C allows 1 to bytes of data to be written into the device during a single internal programming period.
Search field Part name Part description. Address to Output Delay. No data will be written to the device; however, for the duration of t. Manufac- tured with Atmel’s advanced nonvolatile CMOS technology, the device offers access times to ns with power dissipation of just mW. Page Daatasheet Cycle Time: The address is latched on the falling edge of CE or WE, whichever occurs last.
OE to Output Delay. For each WE high to low transition during the page write operation, A6 – A14 must be the same. Atmel has incorporated both hardware and software features that will protect the memory against inadvertent writes.
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. Once a byte write has been started it will automatically time itself to completion. If precautions are not taken, inad- vertent writes may occur during transitions of the host sys- tem power supply.
Fast Write Cycle Datasneet. PROM for device identification or tracking. The device also includes an extra bytes of Daasheet. An optional software data protection mechanism is available to guard against inad- vertent writes. DATA Polling may begin at anytime during the write cycle.
The device contains a byte page register to allow writ- ing of up to bytes simultaneously. Refer to AC Programming Datasheeh. Reading the toggle bit may begin at any time during the 28d256 cycle.
Once the end of a write cycle has been detected a new access for a read or write can begin. The outputs are put in the high impedance state when either CE or OE is high.
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. 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.
After writing the 3-byte command sequence and after t. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. The data is latched by the first rising edge of CE or WE. When enabled, the software data protection SDPwill prevent inadvertent writes. 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. All Output Voltages with Respect to Ground It should be noted, that once protected the host may still perform a byte or page write to the AT28C 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.
This is done by pre- ceding the data to be written by the same 3-byte command sequence used to enable SDP. Please see Soft- ware Chip Erase application note for details.
28C256 – 28C256 256K 250ns Parallel EEPROM Datasheet
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. X can be V. Automatic Page Write Operation. By raising A9 to 12V. Once the write cycle has been completed, true data is valid on all outputs, and the next write cycle may begin. Only bytes which are specified for writing will be written; unnecessary cycling of other bytes within the page does not occur.
Input Test Waveforms and Measurement Level. Hardware features protect against inadvertent writes to the AT28C in the follow- ing ways: