White Electronic Designs
PAGE WRITE OPERATION
These devices have a page write operation that allows one
to 64 bytes of data (one to 128 bytes for the WE512K8) to
be written into the device and then simultaneously written
during the internal programming period. Successive bytes
may be loaded in the same manner after the first data
byte has been loaded. An internal timer begins a time
out operation at each write cycle. If another write cycle
is completed within 150µs or less, a new time out period
begins. Each write cycle restarts the delay period. The write
cycles can be continued as long as the interval is less than
the time out period.
The usual procedure is to increment the least significant
address lines from A
0
through A
5
(A
0
through A
6
for the
WE512K8) at each write cycle. In this manner a page of
up to 64 bytes (128 bytes for the WE512K8) can be loaded
into the EEPROM in a burst mode before beginning the
relatively long interval programming cycle.
After the 150µs time out is completed, the EEPROM
begins an internal write cycle. During this cycle the entire
page of bytes will be written at the same time. The internal
programming cycle is the same regardless of the number
of bytes accessed.
WE512K8, WE256K8,
WE128K8-XCX
The page address must be the same for each byte load
and must be valid during each high to low transition of
WE# (or CS#). The block address also must be the same
for each byte load and must remain valid throughout the
WE# (or CS#) low pulse. The page and block address
lines are summarized below:
PAGE MODE CHARACTERISTICS
V
CC
= 5.0V, V
SS
= 0V, -55°C ≤ T
A
≤ +125°C
Parameter
Write Cycle Time, TYP = 6mS
Data Set-up Time
Data Hold Time
Write Pulse Width
Byte Load Cycle Time
Write Pulse Width High
Device
WE512K8-XCX
WE256K8-XCX
WE128K8-XCX
Symbol
t
WC
t
DS
t
DH
t
WP
t
BLC
t
WPH
Min
100
10
150
150
50
Max
10
Unit
ms
ns
ns
ns
µs
ns
Block Address
A17-A18
A15-A17
A15-A16
Page Address
A7-A16
A6-A14
A6-A14
FIGURE 9 – PAGE WRITE WAVEFORMS
OE#
CS#
WE#
ADDRESS (1)
DATA
NOTE:
1. Decoded Address Lines must be valid for the duration of the write.
White Electronic Designs Corp. reserves the right to change products or specifications without notice.
May 2000
Rev. 1
9
White Electronic Designs Corporation • (602) 437-1520 • www.wedc.com
WEDC [ WHITE ELECTRONIC DESIGNS CORPORATION ]
