w49f102 Winbond Electronics Corp America, w49f102 Datasheet - Page 4

• Manufacturer Part Number: w49f102
• Description: 64k X 16 Cmos Flash Memory
• Manufacturer: Winbond Electronics Corp America

Program Operation
The W49F102 is programmed on a word-by-word basis. Program operation can only change logical
data "1" to logical data "0" The erase operation (changed entire data in main memory and/or boot block
from "0" to "1" is needed before programming.
The program operation is initiated by a 4-word command cycle (see Command Codes for Word
Programming). The device will internally enter the program operation immediately after the word-
program command is entered. The internal program timer will automatically time-out (50 S max. -
T
detect end of program cycle.
Hardware Data Protection
The integrity of the data stored in the W49F102 is also hardware protected in the following ways:
(1) Noise/Glitch Protection: A WE pulse of less than 15 nS in duration will not initiate a write cycle.
(2) V
(3) Write Inhibit Mode: Forcing OE low, CE high, or WE high will inhibit the write operation.
(4) V
Data Polling (DQ
The W49F102 includes a data polling feature to indicate the end of a program or erase cycle.
When the W49F102 is in the internal program or erase cycle, any attempt to read DQ
last word loaded will receive the complement of the true data. Once the program or erase cycle is
completed, DQ
erase cycle, and become logical "1" or true data when the erase cycle has been completed.
Toggle Bit (DQ
In addition to data polling, the W49F102 provides another method for determining the end of a
program cycle. During the internal program or erase cycle, any consecutive attempts to read DQ
DQ
between 0's and 1's will stop. The device is then ready for the next operation.
Product Identification
The product ID operation outputs the manufacturer code and device code. Programming equipment
automatically matches the device with its proper erase and programming algorithms.
The manufacturer and device codes can be accessed by software or hardware operation. In the
software access mode, a six-word (or JEDEC 3-word) command sequence can be used to access the
product ID. A read from address 0000H outputs the manufacturer code (00DAh). A read from address
0001H outputs the device code (002Fh). The product ID operation can be terminated by a three-word
command sequence or an alternate one-word command sequence (see Command Definition table).
In the hardware access mode, access to the product ID is activated by forcing CE and OE low,
WE high, and raising A9 to 12 volts.
BP
14
) once completed and return to normal read mode. Data polling and/or Toggle Bits can be used to
2.5V typical.
This prevents inadvertent writes during power-up or power-down periods.
5 mS before any write (erase/program) operation.
DD
DD
will produce alternating 0's and 1's. When the program or erase cycle is completed, this toggling
power-on delay: When V
Power Up/Down Detection: The programming operation is inhibited when V
7
or DQ
6
& DQ
7 &
15
DQ
will show the true data. Note that DQ
14
15
)- Write Status Detection
)- Write Status Detection
DD
has reached its sense level, the device will automatically time-out
- 4 -
7
or DQ
15
will show logical "0" during the
DD
W49F102
is less than
7
or DQ
15
of the
6
or