FM24V05_10 RAMTRON [Ramtron International Corporation], FM24V05_10 Datasheet - Page 10

• Manufacturer Part Number: FM24V05_10
• Description: 512Kb Serial 3V F-RAM Memory
• Manufacturer: RAMTRON [Ramtron International Corporation]

By FM24VN05
Unique Serial Number (FM24VN05 only)
The FM24VN05 device also incorporates a read-only
8-byte serial number. It can be used to uniquely
identify a pc board or system. The serial number
includes a 40-bit unique number, an 8-bit CRC, and a
16-bit number that can be defined upon request by
the customer. If a customer-specific number is not
requested, the 16-bit Customer Identifier is 0x0000.
The 8 bytes of data are accessed via a Slave Address
sequence similar to the Device ID. The serial number
can be read by the system as follows:
Function to Calculate CRC
BYTE calcCRC8( BYTE* pData, int nBytes )
{
Rev. 2.0
May 2010
By Master
1.
2.
3.
4.
static BYTE crctable[256] = {
* Contact factory for requesting a customer identifier number.
CUSTOMER IDENTIFIER *
SN(63:56)
The master sends a START command
The master sends Reserved Slave ID 0xF8
The master sends the I
the slave device it needs to identify. The last
two bits are ‘Don’t care’ values. Only one
device must acknowledge this byte (the one
that has the I
The master sends a Re-START command
Start
S
Rsvd Slave ID (F8)
0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15,
0x38, 0x3F, 0x36, 0x31, 0x24, 0x23, 0x2A, 0x2D,
0x70, 0x77, 0x7E, 0x79, 0x6C, 0x6B, 0x62, 0x65,
0x48, 0x4F, 0x46, 0x41, 0x54, 0x53, 0x5A, 0x5D,
0xE0, 0xE7, 0xEE, 0xE9, 0xFC, 0xFB, 0xF2, 0xF5,
0xD8, 0xDF, 0xD6, 0xD1, 0xC4, 0xC3, 0xCA, 0xCD,
0x90, 0x97, 0x9E, 0x99, 0x8C, 0x8B, 0x82, 0x85,
0xA8, 0xAF, 0xA6, 0xA1, 0xB4, 0xB3, 0xBA, 0xBD,
0xC7, 0xC0, 0xC9, 0xCE, 0xDB, 0xDC, 0xD5, 0xD2,
0xFF, 0xF8, 0xF1, 0xF6, 0xE3, 0xE4, 0xED, 0xEA,
0xB7, 0xB0, 0xB9, 0xBE, 0xAB, 0xAC, 0xA5, 0xA2,
0x8F, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9D, 0x9A,
0x27, 0x20, 0x29, 0x2E, 0x3B, 0x3C, 0x35, 0x32,
0x1F, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0D, 0x0A,
0x57, 0x50, 0x59, 0x5E, 0x4B, 0x4C, 0x45, 0x42,
2
C-bus slave address).
SN(55:48)
Address
A
2
Slave Address
C-bus slave address of
Figure 15. 8-Byte Serial Number (read-only)
SN(47:40)
Figure 16. Read Serial Number
A
Acknowledge
Start
S
Rsvd Slave ID (CD)
SN(39:32)
Address
40-bit UNIQUE NUMBER
SN(31:24)
A
The 8-bit CRC value can be used to compare to the
value calculated by the controller. If the two values
match, then the communication between slave and
master was performed without errors. The function
(shown below) is used to calculate the CRC value.
To perform the calculation, 7 bytes of data are filled
into a memory buffer in the same order as they are
read from the part – i.e. byte7, byte6, byte5, byte4,
byte3, byte2, byte1 of the serial number. The
calculation is performed on the 7 bytes, and the result
should match the final byte out from the part which is
byte0, the 8-bit CRC value.
5.
6.
Data Byte 7
The master sends Reserved Slave ID 0xCD to
read the serial number.
The master ends the serial number read
sequence by NACKing the last byte, thus
resetting the slave device state machine and
allowing the master to send the STOP
command.
SN(23:16)
A
Acknowledge
FM24V05 - 512Kb I2C FRAM
Data
SN(15:8)
A
Data Byte 0
8-bit CRC
SN(7:0)
Page 10 of 16
Acknowledge
No
1
P
Stop