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Status Register. See the section on the Status

Register for details on the definitions of the Status

Register bits. During the Chip Erase operation the

memory will only accept the Read Status Register

command. All other commands will be ignored.

Typical Chip Erase times are given in Table 12.

The Chip Erase command sets all of the bits in the

memory to ‘1’. See Figure 17, Chip Erase Flow-

chart and Pseudo Code, for a suggested flowchart

on using the Chip Erase command.

Block Erase Command. The Block Erase com-

mand can be used to erase a block. Two Bus Write

operations are required to issue the command; the

second Bus Write cycle latches the block address

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

Register for details on the definitions of the Status

Register bits.

If the block is protected then the Block Erase

operation will abort, the data in the block will not be

changed and the Status Register will output the

error.

Table 11. Commands

Read Memory Array. After a Read Memory Array command, read the memory as normal until another command is issued.

Read Status Register. After a Read Status Register command, read the Status Register as normal until another command is issued.

Read Electronic Signature. After a Read Electronic Signature command, read Manufacturer Code, Device Code until a Read Mem-

ory Array command is issued.

Block Erase, Program. After these commands read the Status Register until the command completes and another command is is-

sued.

differing only for address bit A0 and A1. After this command read the Status Register until the command completes and another com-

mand is issued.

Chip Erase. This command is only valid in A/A Mux mode. After this command read the Status Register until the command completes

and another command is issued.

Clear Status Register. After the Clear Status Register command bits 1, 3, 4 and 5 in the Status Register are reset to ‘0’.

Program/Erase Suspend. After the Program/Erase Suspend command has been accepted, issue Read Memory Array, Read Status

Register, Program (during Erase suspend) and Program/Erase resume commands.

Program/Erase Resume. After the Program/Erase Resume command the suspended Program/Erase operation resumes, read the

Status Register until the Program/Erase Controller completes and the memory returns to Read Mode.

Invalid/Reserved. Do not use Invalid or Reserved commands.

Command

Bus Write Operations

1st

2nd

3rd

4th

5th

Addr

Data

Addr

Data

Addr

Data

Addr

Data

Addr

Data

Read Memory Array

1

X

FFh

Read Status Register

1

X

70h

Read Electronic Signature

1X

90h

1X

98h

Program

2X

40h

PA

PD

2X

10h

PA

PD

Quadruple Byte Program

5

X

30h

PD

PD

PD

PD

Chip Erase

2

X

80h

X

10h

Block Erase

2

X

20h

BA

D0h

Clear Status Register

1

X

50h

Program/Erase Suspend

1

X

B0h

Program/Erase Resume

1

X

D0h

Invalid/Reserved

1X

00h

1X

01h

1X

60h

1X

2Fh

1X

C0h