m29f400b-120n6tr STMicroelectronics, m29f400b-120n6tr Datasheet - Page 11

• Manufacturer Part Number: m29f400b-120n6tr
• Description: 4 Mbit 512kb X8 Or 256kb X16, Boot Block Single Supply Flash Memory
• Manufacturer: STMicroelectronics

M29F400BT, M29F400BB
2.7
2.8
2.9
2.10
Write Enable (W)
The Write Enable, W, controls the Bus Write operation of the memory’s Command Interface.
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.
A Hardware Reset is achieved by holding Reset/Block Temporary Unprotect Low, V
least t
ready for Bus Read and Bus Write operations after t
See the Ready/Busy Output section,
AC Characteristics for more details.
Holding RP at V
and Erase operations on all blocks will be possible. The transition from V
slower than t
Ready/Busy output (RB)
The Ready/Busy pin is an open-drain output that can be used to identify when the memory
array can be read. Ready/Busy is high-impedance during Read mode, Auto Select mode
and Erase Suspend mode.
After a Hardware Reset, Bus Read and Bus Write operations cannot begin until Ready/Busy
becomes high-impedance. See
Characteristics.
During Program or Erase operations Ready/Busy is Low, V
during Read/Reset commands or Hardware Resets until the memory is ready to enter Read
mode.
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 8-bit and 16-bit Bus
modes of the memory. When Byte/Word Organization Select is Low, V
bit mode, when it is High, V
PLPX
. After Reset/Block Temporary Unprotect goes High, V
PHPHH
ID
will temporarily unprotect the protected Blocks in the memory. Program
.
IH
, the memory is in 16-bit mode.
Table 15.
Table 15.
and
Figure
and
Figure
PHEL
11., Reset/Temporary Unprotect AC
or t
11., Reset/Temporary Unprotect
OL
RHEL
. Ready/Busy will remain Low
IH
, whichever occurs last.
, the memory will be
IL
Signal descriptions
, the memory is in 8-
IH
to V
ID
must be
IL
, for at
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