What is the random read command format for EEPROM embedded i

Hi,
What is the random read command format for EEPROM embedded in SDRAM
DIMM, DDR1 DIMM, or DDR2 DIMM?

Micron and Samsung specs fail to mention the format.


Thank you.


Weng

 

[gabor]

The Serial Presence Detect EEPROM on these modules is usually
equivalent to a Microchip 24LC01. However the JEDEC standard
does not specify the size of the EEPROM, and those larger than
256 bytes have different requirements for random read / write.
Thus you would need to first do a serial read starting from the
beginning of the EEPROM to get the part size from the second byte
of SPD and then use the appropriate method for the part used.

The SPD layout for DDR2 DIMM is available as JEDEC document
DDR2 SPD Ver. 1.2, available on line at www.jedec.org

If you don't need code to handle any conceivable DIMM, however
you can usually assume that the SPD device is 128 or 256 bytes
(minimum size to hold required data), and get away with the
single byte subaddress form used by the 24LC01.

wtx@umem.com wrote:

Hi,
What is the random read command format for EEPROM embedded in SDRAM
DIMM, DDR1 DIMM, or DDR2 DIMM?

Micron and Samsung specs fail to mention the format.


Thank you.


Weng