W29C042
Publication Release Date: February 18, 2002
- 5 -
Revision A2
Toggle Bit (DQ6)- Write Status Detection
In addition to data polling, the W29C042 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.
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 "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.
TABLE OF OPERATING MODES
Operating Mode Selection
Operating Range: 0 to 70
° C (Ambient Temperature), VDD = 5V ±10 %, VSS = 0V, VHH = 12V
MODE
PINS
#CE
#OE
#WE
ADDRESS
DQ.
Read
VIL
VIH
AIN
Dout
Write
VIL
VIH
VIL
AIN
Din
Standby
VIH
X
High Z
Write Inhibit
X
VIL
X
High Z/DOUT
X
VIH
X
High Z/DOUT
Output Disable
X
VIH
X
High Z
Product ID
VIL
VIH
A0 = VIL; A1
A18 = VIL;
A9 = VHH
Manufacturer Code DA
(Hex)
VIL
VIH
A0 = VIH; A1
A18 = VIL;
A9 = VHH
Device Code
46 (Hex)