W29C040P-70B Winbond Electronics, W29C040P-70B Datasheet - Page 6

• Manufacturer Part Number: W29C040P-70B
• Manufacturer: Winbond Electronics

Specifications of W29C040P-70B

• Density: 4Mb
• Access Time (max): 70ns
• Interface Type: Parallel
• Boot Type: Bottom/Top
• Address Bus: 19b
• Operating Supply Voltage (typ): 5V
• Operating Temp Range: 0C to 70C
• Package Type: PLCC
• Program/erase Volt (typ): 5V
• Sync/async: Asynchronous
• Operating Temperature Classification: Commercial
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (max): 5.5V
• Word Size: 8b
• Number Of Words: 512K
• Supply Current: 50mA
• Mounting: Surface Mount
• Pin Count: 32
• Lead Free Status / Rohs Status: Supplier Unconfirmed

6.7
The W29C040 includes a data polling feature to indicate the end of a write cycle. When the W29C040
is in the internal write 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 write cycle is completed. DQ7 will show
the true data. See the #DATA Polling Timing Diagram.
6.8
In addition to data polling, the W29C040 provides another method for determining the end of a write
cycle. During the internal write cycle, any consecutive attempts to read DQ6 will produce alternating
0's and 1's. When the write cycle is completed, this toggling between 0's and 1's will stop. The device
is then ready for the next operation. See Toggle Bit Timing Diagram.
6.9
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 "00000 hex" outputs the manufacturer code "DA hex." A read from address "00001 hex"
outputs the device code "46 hex." 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.
Data Polling (DQ7)- Write Status Detection
Toggle Bit (DQ6)- Write Status Detection
Product Identification
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W29C040