SPD DDR fixture
SPD is a DDR important part,we make this DDR fixture for customer testing the DDR memory particles.
We also provide the SPD information for Customers testing reference.
What is SPD?
1. SPD is the abbreviation of SERIAL PRESENCE DETECT. Chinese means serial detection of module existence. That is, the information of the module in the memory slot is checked by the EEPROM of the IIC serial interface mentioned above. In this case, the module-related information must be recorded in the EEPROM. Customary, we call this EEPROM IC SPD. It is the abbreviation of Serial Presence Detect, which is the code burned in EEPROM. In the past, the BIOS must detect the memory when booting, but with SPD, it is no longer necessary to detect the action, and the BIOS directly reads the SPD to obtain the memory. Relevant information.
2, SPD is a set of configuration information about the memory module, such as the number of P-Bank, voltage, row address / column address number, bit width, various major operational timing (such as CL, tRCD, tRP, tRAS, etc.)...... They are stored in an EEPROM (Electrically Erasable Programmable Read Only Memory) with a capacity of 256 bytes.
3. In fact, in SPD, the standard information specified by JEDEC uses only 128 bytes (and 128 bytes, which belongs to the manufacturer's own dedicated area). Generally, one byte corresponds to at least one parameter, and some parameters require multiple bytes to be expressed (such as the product serial number, the code of the manufacturer in the JEDEC organization).
Among them, each bit in a byte may be used to indicate the specific value of this parameter. Because SPD has a lot of information, it is not listed here. Interested readers can refer to related documents.
4. The timing information in the SPD is written and written to the EEPROM by the module manufacturer according to the characteristics of the used memory chip. The main purpose is to assist the Northbridge chip to accurately adjust the physical/timing parameters of the memory to achieve the best use effect. If the BIOS setting option is set to "By SPD" in the BIOS. Then, at the time of power on, the North Bridge will automatically configure the corresponding memory timing and control registers according to the parameter information in the SPD to avoid human error caused by the calibration error. Of course, for DIYer, timing and control parameters can also be freely adjusted (physical parameters are still determined by SPD or Northbridge self-test).
Recently,many customers ask us to provide this SPD,because the DDR memory partcle have different type and brand. When test, it need to different configuration.
So this SPD information can help customers test the chip well and efficient with right configuration.
If you also have this test requirements,please contact with me freely.