wp@iddth.id.dk (Wiesiek Pawlowski (900415#GUEST)) (04/19/91)
Hello, one of my friends has bought a 386SX/16MHz system resently and he has some strange problems with it. The computer simply "hangs" from time to time without any explicit reason. My friend has a conjecture about it. He thinks that the problem is caused by improper DRAMs. The documen- tation of the motherboard says that the system should use "100ns fast page mode DRAMs with the following critical DRAM specifications: tCAS<=35ns, tCAC<=35ns, tCP<=20ns". and then it "explains" the terminology: tCAS - CAS pulse width tCAC - CAS access time tCP - CAS prechage time What are these parameters? What do they mean? Does it mean that there are different 100ns DRAM chips? Are they marked with these additional parameters? I mean - is it written on the chip that it has tCAS<=35ns for example? Totally confused, Wiesiek.
mj@hpihoah.cup.hp.com (Marlin Jones) (04/25/91)
> From wp@iddth.id.dk Fri Apr 19 08:25:48 1991 > "100ns fast page mode DRAMs with the following critical DRAM specifications: > tCAS<=35ns, tCAC<=35ns, tCP<=20ns". > and then it "explains" the terminology: > tCAS - CAS pulse width > tCAC - CAS access time > tCP - CAS prechage time > What are these parameters? What do they mean? Does it mean that there are These are timing parameters on the waveforms that are supplied to each DRAM. It would be pretty hard to explain these without a timing diagram - what you need is to look at a DRAM vendor's data book. Some databooks that come to mind: Texas Instruments, "MOS Memory Data Book" Mitsubishi, "Semiconductor Memories Data Book" Toshiba, "MOS Memory Data Book" > different 100ns DRAM chips? Are they marked with these additional parameters? No. Each vendor has slightly different specifications for each "100 ns" DRAM. You need to look at each vendor's data book and find out what values they have for these parameters. *OR*, you could have your friend call the folks that sold him the system and ask for the specific DRAM vendor's that meet the specs. > I mean - is it written on the chip that it has tCAS<=35ns for example? Nope. > Totally confused, > Wiesiek. Hope this helps. mj Marlin Jones hplabs!hpda!mj mj@hpda.hp.com "I practice safe motorcycling - I keep the rubber on the road."