what is serial presence detect sdram?

[catls]

im buying a ca180 motherboard and it needs serial presence detect sdram at 100mhz.what is serial presence detect?where can i find more info about it?

[Roy]

In simple terms, it is PC100 SDRAM. (With or without ECC ~ Error Code Correction)

Presence Detect is a means of identifying a memory chip to the memory controller logic. The original scheme, called Parallel Presence Detect (PPD) used a separate pin for each bit of information. As the number of pins can not be very large, this only allowed to identify the density and the speed of the chips.

To allow for additional information, the Serial Presence Detect (SPD) scheme was introduced which uses a serial EEPROM to store the presence detect information and requires only two pins (one for enabling it and one for data).

This will be on the Mid-term. /forum/wink.gif

[kwai]

serial presence detect (spd) lets memory modules tell the motherboard what timings it can handle, so that you don't have to enter those values manually in the BIOS.

i think the "memory man" retailer specifies which mem modules are spd enabled, but most recent pc100 memory is spd compliant.

[biggdogg]

I just purchased a 32 meg chip for my presario (pc66) from compusa. They swore me up and down that it would work but my computer only recognized 8 megs of the 32 megs.. AAAARRRRGGGHHHH!
Is there ANY way around this ?

Thanks!!