M50LPW080 datasheet(16/44 Pages) STMICROELECTRONICS

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M50LPW080

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COMMAND INTERFACE

All Bus Write operations to the memory are inter-

preted by the Command Interface. Commands

consist of one or more sequential Bus Write oper-

ations.

After power-up or a Reset operation the memory

enters Read mode.

The commands are summarized in Table 10.. The

following text descriptions should be read in con-

junction with Table 10..

Read Memory Array Command. The

Read

Memory Array command returns the memory to its

Read mode where it behaves like a ROM or

EPROM. One Bus Write cycle is required to issue

the Read Memory Array command and return the

memory to Read mode. Once the command is is-

sued the memory remains in Read mode until an-

other command is issued. From Read mode Bus

Read operations will access the memory array.

While the Program/Erase Controller is executing a

Program or Erase operation the memory will not

accept the Read Memory Array command until the

operation completes.

Read Status Register Command. The

Read

Status Register command is used to read the Sta-

tus Register. One Bus Write cycle is required to is-

sue the Read Status Register command. Once the

command is issued subsequent Bus Read opera-

tions read the Status Register until another com-

mand is issued. See the section on the Status

Read Electronic Signature Command. The Read

Electronic Signature command is used to read the

Manufacturer Code and the Device Code. One

Bus Write cycle is required to issue the Read Elec-

tronic Signature command. Once the command is

issued subsequent Bus Read operations read the

Manufacturer Code or the Device Code until an-

other command is issued.

After the Read Electronic Signature Command is

issued the Manufacturer Code and Device Code

can be read using Bus Read operations using the

addresses in Table 9..

Table 9. Read Electronic Signature

Program Command. The

Program

command

can be used to program a value to one address in

the memory array at a time. Two Bus Write opera-

tions are required to issue the command; the sec-

ond Bus Write cycle latches the address and data

in the internal state machine and starts the Pro-

gram/Erase Controller. Once the command is is-

sued subsequent Bus Read operations read the

Status Register. See the section on the Status

If the address falls in a protected block then the

Program operation will abort, the data in the mem-

ory array will not be changed and the Status Reg-

ister will output the error.

During the Program operation the memory will

only accept the Read Status Register command

and the Program/Erase Suspend command. All

other commands will be ignored. Typical Program

times are given in Table 15..

Note that the Program command cannot change a

bit set at ‘0’ back to ‘1’ and attempting to do so will

not cause any modification on its value. One of the

Erase commands must be used to set all of the

bits in the block to ‘1’.

See Figure 17. for a suggested flowchart on using

the Program command.

Quadruple Byte Program Command. The Qua-

druple Byte Program Command can be only used

in A/A Mux mode to program four adjacent bytes

in the memory array at a time. The four bytes must

differ only for the addresses A0 and A10. Pro-

gramming should not be attempted when VPP is

not at VPPH. The operation can also be executed if

VPP is below VPPH, but result could be uncertain.

Five Bus Write operations are required to issue the

command. The second, the third and the fourth

Bus Write cycle latches respectively the address

and data of the first, the second and the third byte

in the internal state machine. The fifth Bus Write

cycle latches the address and data of the fourth

byte in the internal state machine and starts the

Program/Erase Controller. Once the command is

issued subsequent Bus Read operations read the

Status Register. See the section on the Status

During the Quadruple Byte Program operation the

memory will only accept the Read Status register

command and the Program/Erase Suspend com-

mand. All other commands will be ignored. Typical

Quadruple Byte Program times are given in Table

15..

Note that the Quadruple Byte Program command

cannot change a bit set to ‘0’ back to ‘1’ and at-

tempting to do so will not cause any modification

on its value. One of the Erase commands must be

used to set all of the bits in the block to ‘1’.

See Figure 18. for a suggested flowchart on using

the Quadruple Byte Program command.

Code

Address

Data

Manufacturer Code

00000h

20h

Device Code

00001h

2Fh

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