W29EE012
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Hardware Data Protection
The integrity of the data stored in the W29EE012 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) VDD Power Up/Down Detection: The programming and operation are inhibited when VDD is less
than 3.8V.
(3) Write Inhibit Mode: Forcing #OE low, #CE high, or #WE high will inhibit the write operation. This
prevents inadvertent writes during power-up or power-down periods.
Data Polling (DQ7)-Write Status Detection
The W29EE012 includes a data polling feature to indicate the end of a programming cycle. When the
W29EE012 is in the internal programming cycle, any attempt to read DQ7 of the last byte loaded during
the page/byte-load cycle will receive the complement of the true data. Once the programming cycle is
completed. DQ7 will show the true data.
Toggle Bit (DQ6)-Write Status Detection
In addition to data polling, the W29EE012 provides another method for determining the end of a
program cycle. During the internal programming cycle, any consecutive attempts to read DQ6 will
produce alternating 0's and 1's. When the programming cycle is completed, this toggling between 0's
and 1's will stop. The device is then ready for the next operation.
5-Volt-Only Software Chip Erase
The chip-erase mode can be initiated by a six-byte command sequence. After the command loading
cycles, the device enters the internal chip erase mode, which is automatically timed and will be
completed in 50 mS. The host system is not required to provide any control or timing during this
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-byte command sequence can be used to access the product ID. A read
from address 0000H outputs the manufacturer code (DAh). A read from address 0001H outputs the
device code (C1h). The product ID operation can be terminated by a three-byte command sequence.
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.
Note: The hardware SID read function is not included in all parts; please refer to Ordering Information for details.
