M50FLW040ANB5TP View Datasheet(PDF) - STMicroelectronics

Part Name

Description

MFG CO.

M50FLW040ANB5TP

4-Mbit (5 × 64 Kbyte blocks + 3 × 16 × 4 Kbyte sectors) 3-V supply Firmware Hub / low-pin count Flash memory

STMicroelectronics 

M50FLW040A, M50FLW040B

Command interface

4.0.2

4.0.3

4.0.4

Read Status Register command

The Read Status Register command is used to read the Status Register. One Bus Write

cycle is required to issue the Read Status Register command. Once the command is issued,

subsequent Bus Read operations read the Status Register until another command is issued.

See the section on the Status Register for details on the definitions of the Status Register

bits.

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 Electronic Signature

command. Once the command is issued, the Manufacturer Code and Device Code can be

read using conventional Bus Read operations, and the addresses shown in Table 12.

Table 12. Electronic signature codes

Code

Address(1)

Data

Manufacturer Code

Device Code

M50FLW040A

M50FLW040B

...00000h

20h

...00001h

08h

28h

1. A22 should be ‘1’, and the ID lines and upper address bits should be set according to the rules illustrated in

Table 5, Table 6 and Table 8.

The device remains in this mode until another command is issued. That is, subsequent Bus

Read operations continue to read the Manufacturer Code, or the Device Code, and not the

Memory Array.

Program command

The Program command can be used to program a value to one address in the memory array

at a time.

The Program command works by changing appropriate bits from ‘1’ to ‘0’. (It cannot change

a bit from ‘0’ back to ‘1’. Attempting to do so will not modify the value of the bit. Only the

Erase command can set bits back to ‘1’. and does so for all of the bits in the block.)

Two Bus Write operations are required to issue the Program command. The second Bus

Write cycle latches the address and data, and starts the Program/Erase Controller.

Once the command is issued, subsequent Bus Read operations read the value in the Status

Register. (See the section on the Status Register for details on the definitions of the Status

Register bits.)

If the address falls in a protected block, the Program operation will abort, the data in the

memory array will not be changed, and the Status Register will indicate 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 are ignored.

See Figure 21, for a suggested flowchart on using the Program command. Typical Program

times are given in Table 18.

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