Table of operating modes – Rainbow Electronics W29C040 User Manual
Page 5
W29C040
Publication Release Date: May 1999
- 5 -
Revision A5
Toggle Bit (DQ6)- Write Status Detection
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.
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), V
DD
= 5V
±
10%, V
SS
= 0V, V
HH
= 12V
MODE
PINS
CE
OE
WE
ADDRESS
DQ.
Read
V
IL
V
IL
V
IH
A
IN
Dout
Write
V
IL
V
IH
V
IL
A
IN
Din
Standby
V
IH
X
X
X
High Z
Write Inhibit
X
V
IL
X
X
High Z/D
OUT
X
X
V
IH
X
High Z/D
OUT
Output Disable
X
V
IH
X
X
High Z
Product ID
V
IL
V
IL
V
IH
A0 = V
IL
; A1
−
A18 = V
IL
;
A9 = V
HH
Manufacturer Code DA
(Hex)
V
IL
V
IL
V
IH
A0 = V
IH
; A1
−
A18 = V
IL
;
A9 = V
HH
Device Code
46 (Hex)