AT49BV008A(T)/8192A(T)
5
For details, see Operating Modes (for hardware operation)
or Software Product Identification. The manufacturer and
device code is the same for both modes.
DATA POLLING:
The AT49BV008A(T)/8192A(T) features
DATA polling to indicate the end of a program cycle. During
a program cycle an attempted read of the last byte loaded
will result in the complement of the loaded data on I/O7.
Once the program cycle has been completed, true data is
valid on all outputs and the next cycle may begin. During a
chip or sector erase operation, an attempt to read the
device will give a “0” on I/O7. Once the program or erase
cycle has completed, true data will be read from the device.
DATA polling may begin at any time during the program
cycle.
TOGGLE BIT:
In addition to DATA polling the
AT49BV008A(T)/8192A(T) provides another method for
determining the end of a program or erase cycle. During a
program or erase operation, successive attempts to read
data from the device will result in I/O6 toggling between
one and zero. Once the program cycle has completed, I/O6
will stop toggling and valid data will be read. Examining the
toggle bit may begin at any time during a program cycle.
READY/BUSY:
For the AT49F008A(T), pin 12 is an open
drain READY/BUSY output pin which provides another
method of detecting the end of a program or erase opera-
tion. RDY/BUSY is actively pulled low during the internal
program and erase cycles and it is released at the comple-
tion of the cycle. The open drain connection allows for OR-
tying of several devices to the same RDY/BUSY line.
HARDWARE DATA PROTECTION:
Hardware features
protect against inadvertent programs to the
AT49BV008A(T)/8192A(T) in the following ways: (a) V
CC
sense: if V
CC
is below 1.8V (typical), the program function
is inhibited. (b) V
CC
power on delay: once V
CC
has reached
the V
CC
sense level, the device will automatically time out
10 ms (typical) before programming. (c) Program inhibit:
holding any one of OE low, CE high or WE high inhibits
program cycles. (d) Noise filter: pulses of less than 15 ns
(typical) on the WE or CE inputs will not initiate a program
cycle.
INPUT LEVELS:
While operating with a 2.7V to 3.6V
power supply, the address inputs and control inputs (OE,
CE, and WE) may be driven from 0 to 5.5V without
adversely affecting the operation of the device. The I/O
lines can only be driven from 0 to V
CC
+ 0.6V.
AT49BV008A(T) ALTERNATE PIN DEFINITION:
Two
AT49BV008A(T) BGA pin definitions are shown. The stan-
dard pin definition allows use of the JEDEC standard pro-
gramming algorithm. If the alternate pin definition is used,
the programming algorithm must be modified as shown in
the Command Definition for Alternate Pin Definition Table
on page 7.