M29DW128F datasheet(16/94 Pages) STMICROELECTRONICS

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Signal descriptions

M29DW128F

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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 the blocks previously protected using a High Voltage

Block Protection technique (In-System or Programmer technique).

Note that if VPP/WP is at VIL, then the four outermost parameter blocks will remain protected

even if RP is at VID.

A Hardware Reset is achieved by holding Reset/Block Temporary Unprotect Low, VIL, for at

least tPLPX. After Reset/Block Temporary Unprotect goes High, VIH, the memory will be

ready for Bus Read and Bus Write operations after tPHEL or tRHEL, whichever occurs last.

See the Ready/Busy Output section, Table 30: Reset/Block Temporary Unprotect AC

characteristics and Figure 18 and Figure 19 for more details.

Holding RP at VID will temporarily unprotect all the blocks previously protected using a High

Voltage Block Protection technique. Program and erase operations on all blocks will be

possible. The transition from VIH to VID must be slower than tPHPHH.

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, VOL. 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 Table 30: Reset/Block Temporary Unprotect AC

characteristics and Figure 18 and Figure 19.

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)

It is used to switch between the x8 and x16 Bus modes of the memory when the

M29DW128F is delivered in TSOP56 package. 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.

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