Signal descriptions
M29W320DT, M29W320DB
2.10
Ready/Busy Output (RB)
The Ready/Busy pin is an open-drain output that can be used to identify when the device is
performing a Program or Erase operation. During Program or Erase operations Ready/Busy
is Low, V
OL
. Ready/Busy is high-impedance during Read mode, Auto Select mode and
Erase Suspend mode.
Note that if V
PP
/WP is at V
IL
, then the 16 KByte outermost boot block will remain protect
even if RP is at V
ID
.
After a Hardware Reset, Bus Read and Bus Write operations cannot begin until Ready/Busy
becomes high-impedance. See
and
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.
2.11
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, V
IL
, the memory is in
x8 mode, when it is High, V
IH
, the memory is in x16 mode.
2.12
V
CC
Supply Voltage
V
CC
provides the power supply for all operations (Read, Program and Erase).
The Command Interface is disabled when the V
CC
Supply Voltage is less than the Lockout
Voltage, V
LKO
. This prevents Bus Write operations from accidentally 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 memory contents
being altered will be invalid.
A 0.1µF capacitor should be connected between the V
CC
Supply Voltage pin and the V
SS
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, I
CC3
.
2.13
V
SS
Ground
V
SS
is the reference for all voltage measurements.
14/56
NUMONYX [ NUMONYX B.V ]
