M29W640GH, M29W640GL, M29W640GT, M29W640GB
Signal descriptions
2.9
Reset/Block Temporary Unprotect (RP)
The Reset/Block Temporary Unprotect pin can be used to apply a Hardware Reset to the
memory or to temporarily unprotect all Blocks that have been protected.
Note that if V /WP is at V , then the two or four outermost blocks will remain protected
PP
IL
even if RP is at V .
ID
A Hardware Reset is achieved by holding Reset/Block Temporary Unprotect Low, V , for at
IL
least t
. After Reset/Block Temporary Unprotect goes High, V , the memory will be
PLPX
IH
ready for Bus Read and Bus Write operations after t
or t
, whichever occurs last.
RHEL
PHEL
See the Ready/Busy Output section, Table 20: Reset/Block Temporary Unprotect ac
Characteristics and Figure 17: Reset/Block Temporary Unprotect ac waveforms, for more
details.
Holding RP at V will temporarily unprotect the protected Blocks in the memory. Program
ID
and Erase operations on all blocks will be possible. The transition from V to V must be
IH
ID
slower than t
.
PHPHH
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 . Ready/Busy is high-impedance during Read mode, Auto Select mode and
OL
Erase Suspend mode.
After a Hardware Reset, Bus Read and Bus Write operations cannot begin until Ready/Busy
becomes high-impedance. See Table 20: Reset/Block Temporary Unprotect ac
Characteristics and Figure 17: Reset/Block Temporary Unprotect ac waveforms, for more
details.
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 , the memory is in
IL
x8 mode, when it is High, V , the memory is in x16 mode.
IH
17/90
NUMONYX [ NUMONYX B.V ]
