M29W320ET, M29W320EB
Ready/Busy is Low, VOL. Ready/Busy is high-im-
pedance during Read mode, Auto Select mode
and Erase Suspend mode.
VCC Supply Voltage (2.7V to 3.6V). VCC
pro-
vides the power supply for all operations (Read,
Program and Erase).
After a Hardware Reset, Bus Read and Bus Write
operations cannot begin until Ready/Busy be-
comes high-impedance. See Table 16. and Figure
16., Reset/Block Temporary Unprotect AC Wave-
forms.
The use of an open-drain output allows the Ready/
Busy pins from several memories to be connected
to a single pull-up resistor. A Low will then indicate
that one, or more, of the memories is busy.
Byte/Word Organization Select (BYTE). The
Byte/Word Organization Select pin is used to
switch between the x8 and x16 Bus modes of the
memory. When Byte/Word Organization Select is
Low, VIL, the memory is in x8 mode, when it is
High, VIH, the memory is in x16 mode.
The Command Interface is disabled when the VCC
Supply Voltage is less than the Lockout Voltage,
V
LKO. This prevents Bus Write operations from ac-
cidentally damaging the data during power up,
power down and power surges. If the Program/
Erase Controller is programming or erasing during
this time then the operation aborts and the memo-
ry contents being altered will be invalid.
A 0.1µF capacitor should be connected between
the VCC Supply Voltage pin and the VSS Ground
pin to decouple the current surges from the power
supply. The PCB track widths must be sufficient to
carry the currents required during Program and
Erase operations, ICC3
.
VSS Ground. VSS is the reference for all voltage
measurements. The device features two VSS pins
which must be both connected to the system
ground.
11/46
STMICROELECTRONICS [ ST ]
