Table of operating modes – Rainbow Electronics W29C020C User Manual
Page 5
W29C020C
Publication Release Date: April 1999
- 5 -
Revision A1
Toggle Bit (DQ6)- Write Status Detection
In addition to data polling, the W29C020C 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. The programming equipment
automatically matches the device with its proper erase and programming algorithms.
The manufacturer and device codes can be accessed through software or by 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 "45 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
−
A17 = V
IL
;
A9 = V
HH
Manufacturer Code DA
(Hex)
V
IL
V
IL
V
IH
A0 = V
IH
; A1
−
A17 = V
IL
;
A9 = V
HH
Device Code
45 (Hex)