allred@ut-emx.UUCP (Kevin L. Allred) (07/21/89)
I have some SIMMS that I'm installing in a 386SX motherboard. The installation manual doesn't say how to tell if SIMMS are page mode capable or not. I set the switches for non page mode since I think that is what they are. Can some one with a lot of memory experience tell me if the SIMMS are page mode capable. The number on the individual drams is: TC511000J (They are TI SIMMS.) Now the next question is probably of general interest. What is page mode memory access, and how is it different than other memory access techniques. -- Kevin Allred allred@emx.cc.utexas.edu allred@ut-emx.UUCP
ray@ole.UUCP (Ray Berry) (07/21/89)
> that is what they are. Can some one with a lot of memory experience > tell me if the SIMMS are page mode capable. The number on the > individual drams is: > TC511000J Yes these are page mode parts. However, you should realize that in DRAMS, page mode == "run-of-the-mill"; i.e., the page mode operation is an attribute of your normal b-flat drams. > Now the next question is probably of general interest. What is page > mode memory access, and how is it different than other memory access > techniques. Generally speaking, there are three flavors of DRAM's going around these days: (1) page mode, (2) nibble mode, and (3) static column. In drams, the ram address is loaded into the chip in two halves. First a "row" address is strobed in, and then a "column" address. To save time, you can get data from other columns which have the same row address without repeatedly loading the row address. The details of how you go about doing this relates to the three modes above: (1) you present a new column address and then strobe it in. This is what "page-mode" means. (2) You don't bother changing the column address, you simply clock the column strobe line and the data from successive column addresses comes tripping out. This is "nibble-mode". (3) You don't bother driving the column strobe line, you simply change the column address and you get the contents of that cell with no further ado. This is "static-column". A further generalization is that for 1 meg chips, parts ending with a '0' are page mode devices (e.g. 511000); parts ending with a '1' are nibble mode types, and parts ending with a '2' are static column (e.g. 511002). I reiterate that this is a generalization- some mfr's use totally different numbering schemes. I believe static column parts were first used on pc's on the original Compaq 386-16, and again on boards which imitated the Compaq design, such as Micronics. -- Ray Berry kb7ht uucp: ...{sumax|thebes}!ole!ray COMPU$ERVE: 73407,3152 Seattle Silicon Corp. 3075 112th Ave NE. Bellevue WA 98004 (206) 828 4422