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M29F512B

Table 4. Commands

Note: X Don’t Care, PA Program Address, PD Program Data.

All values in the table are in hexadecimal.

The Command Interface only uses address bits A0-A10 to verify the commands, the upper address bits are Don’t Care.

Read/Reset. After a Read/Reset command, read the memory as normal until another command is issued.

Auto Select. After an Auto Select command, read Manufacturer ID or Device ID.

Program, Unlock Bypass Program, Chip Erase. After these commands read the Status Register until the Program/Erase Controller com-

pletes and the memory returns to Read Mode.

Unlock Bypass. After the Unlock Bypass command issue Unlock Bypass Program or Unlock Bypass Reset commands.

Unlock Bypass Reset. After the Unlock Bypass Reset command read the memory as normal until another command is issued.

Command

Bus Write Operations

1st

2nd

3rd

4th

5th

6th

Addr

Data

Addr

Data

Addr

Data

Addr

Data

Addr

Data

Addr

Data

Read/Reset

1X

F0

3

555

AA

2AA

55

X

F0

Auto Select

3

555

AA

2AA

55

555

90

Program

4

555

AA

2AA

55

555

A0

PA

PD

Unlock Bypass

3

555

AA

2AA

55

555

20

Unlock Bypass

Program

2X

A0

PA

PD

Unlock Bypass Reset

2

X

90

X

00

Chip Erase

6

555

AA

2AA

55

555

80

555

AA

2AA

55

555

10

From the Auto Select mode the Manufacturer

Code can be read using a Bus Read operation

Code for STMicroelectronics is 20h.

The Device Code can be read using a Bus Read

Device Code for the M29F512B is 24h.

Program Command. The

Program

command

can be used to program a value to one address in

the memory array at a time. The command re-

quires four Bus Write operations, the final write op-

eration latches the address and data in the internal

state machine and starts the Program/Erase Con-

troller.

During the program operation the memory will ig-

nore all commands. It is not possible to issue any

command to abort or pause the operation. Typical

program times are given in Table 5. Bus Read op-

erations during the program operation will output

the Status Register on the Data Inputs/Outputs.

See the section on the Status Register for more

details.

After the program operation has completed the

memory will return to the Read mode, unless an

error has occurred. When an error occurs the

memory will continue to output the Status Regis-

ter. A Read/Reset command must be issued to re-

set the error condition and return to Read mode.

Note that the Program command cannot change a

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

cause an error. The Chip Erase command must be

used to set all the bits in the memory from ’0’ to ’1’.

Unlock Bypass Command. The Unlock Bypass

command is used in conjunction with the Unlock

Bypass Program command to program the memo-

ry. When the access time to the device is long (as

with some EPROM programmers) considerable

time saving can be made by using these com-

mands. Three Bus Write operations are required

to issue the Unlock Bypass command.

Once the Unlock Bypass command has been is-

sued the memory will only accept the Unlock By-

pass Program command and the Unlock Bypass

Reset command. The memory can be read as if in

Read mode.