CAT28C256

7

Doc. No. 25020-0A 2/98

Page Write

The page write mode of the CAT28C256 (essentially an

extended BYTE WRITE mode) allows from 1 to 64 bytes

cycle. This effectively reduces the byte-write time by a

factor of 64.

Following an initial WRITE operation (

WE pulsed low, for

issuing sequential

WE pulses, which load the address

and data bytes into a 64 byte temporary buffer. The page

(which can be loaded in any order) during the first and

subsequent write cycles. Each successive byte load

preceding

WE pulse. There is no page write window

limitation as long as

Upon completion of the page write sequence,

WE must

matic program cycle to commence. This programming

cycle consists of an erase cycle, which erases any data

that existed in each addressed cell, and a write cycle,

which writes new data back into the cell. A page write will

only write data to the locations that were addressed and

will not rewrite the entire page.

Figure 5. Byte Write Cycle [CE Controlled]

5096 FHD F07

Figure 6. Page Mode Write Cycle

OE

CE

WE

ADDRESS

I/O

tWP

tBLC

BYTE 0

BYTE 1

BYTE 2

BYTE n

BYTE n+1

BYTE n+2

LAST BYTE

tWC

5096 FHD F10

ADDRESS

CE

OE

WE

DATA OUT

tAS

DATA IN

DATA VALID

HIGH-Z

tAH

tWC

tOEH

tDH

tDS

tOES

tBLC

tCH

tCS

tCW