FM24V02 - 256Kb I2C FRAM

Rev. 3.0

Jan. 2012

Page 9 of 16

Device ID

The FM24V02 and FM24VN02 devices incorporate a

means of identifying the device by providing three

bytes of data, which are manufacturer, product ID,

and die revision. The Device ID is read-only. It can

be accessed as follows:

1.

The master sends a START command.

2.

The master sends Reserved Slave ID 0xF8

3.

The master sends the I

of the slave device it needs to identify. The

last bit is a ‘Don’t care’ value (R/W bit).

Only one device must acknowledge this byte

(the one that has the I

4.

The master sends a Re-START command.

5.

The master sends Reserved Slave ID 0xF9

6.

The Device ID Read can be done, starting

with the 12 manufacturer bits, followed by

the 9 part identification bits, and then the 3

die revision bits.

7.

The master ends the Device ID read

sequence by NACKing the last byte, thus

resetting the slave device state machine and

allowing the master to send the STOP

command.

Note: The reading of the Device ID can be stopped

anytime by sending a NACK command.

S

A

Data Byte

Data Byte

1

P

By Master

By FM24V02

Start

Address

Stop

No

Acknowledge

Data

S

A

Rsvd Slave ID (F8)

Slave Address

A

Start

Address

Acknowledge

Rsvd Slave ID (F9)

A

A

Data Byte

Acknowledge

Figure 13. Read Device ID

Manufacturer ID

Product ID

Die Rev.

11

10

9

8

7

6

5

4

3

2

1

0

8

7

6

5

4

3

2

1

0

2

1

0

Ramtron

Density

Variation

0

0

0

0

0

0

0

0

0

1

0

0

0

0

1

0

N

0

0

0

0

0

0

0

Figure 14. Manufacturer and Product ID

Density: 01h=128Kb, 02h=256Kb, 03h=512Kb, 04=1Mb

Variation: Product ID bit 4 = S/N, Product ID bit 0 = reserved

The 3-byte hex code for an FM24V02 will be:

0x00 0x42 0x00

The 3-byte hex code for an FM24VN02 will be:

0x00 0x42 0x80