Integrated Silicon Solution, Inc. — 1-800-379-4774

5

REV. A

11/01/01

IS23SC4418

IS23SC4428

Table 1. Control Words for IS23SC4418/4428 Commands

Command Name

Byte 1

Byte 2

Byte 3

S0 S1 S2 S3 S4 S5

A8 A9

A0-A7

D0-D7

Read 8-bits data without protect bit

011100

A8 A9

A0-A7

Don't Care

Read 9-bits data with protect bit

001100

A8 A9

A0-A7

Don't Care

110011

A8 A9

A0-A7

Input data

100011

A8 A9

A0-A7

Input data

000011

A8 A9

A0-A7

Compare data

Write Error Counter

010011

1

1

FDH

Bit Mask

Verify first PSC byte

101100

1

1

FEH

PSC byte 1

Verify second PSC byte

101100

1

1

FFH

PSC byte 2

Write and erase first PSC byte

110011

1

1

FEH

PSC byte 1

Write and erase second PSC byte

110011

1

1

FFH

PSC byte 2

Write and erase first PSC byte

100011

1

1

FEH

PSC byte 1

Write and erase second PSC byte

100011

1

1

FFH

PSC byte 2

Read 8-bits first PSC byte

011100

1

1

FEH

Don't Care

Read 8-bits second PSC byte

011100

1

1

FFH

Don't Care

without protect bit

Read 9-bits first PSC byte

001100

1

1

FEH

Don't Care

with protect bit

Read 9-bits second PSC byte

001100

1

1

FFH

Don't Care

with protect bit

Notes:

1. If the protect bit of the byte address is enabled, the write command will have no effect on the byte content.

2. If the protect bit of the PSC byte is enabled, the write command will have no effect on the PSC byte.

3. For IS23SC4428, locations (1021-1023) are occupied by Error Counter and PSC codes and thus cannot be used for general data

storage.