rogers@iris.ucdavis.edu (Brewski Rogers) (12/09/90)
How exactly do static column RAMs work? I know you get the first word in the normal amount of time, and following words from the same column much quicker, but how MUCH quicker? Also, do you have to do anything special to read static column RAMs, or do they magically figure out that you asked for 4 sequential words? I'd be extremely thankful for any illumination! -bruce ------------------------------------------------------ Quantum _\/_ 2822 Ganges Bruce (6502 RULES!) Rogers |\ Duck ( 0 0) Davis, Ca 95616 Quantum Duck Software, |\ \______/ / \\\ 916-753-7158 rogers@iris.ucdavis.edu |\ < < | \/ Cinnamon, Rock Candy, or Sugar? decisions decisions. \_________/ Quark!
daveh@cbmvax.commodore.com (Dave Haynie) (12/11/90)
In article <9460@aggie.ucdavis.edu> rogers@iris.ucdavis.edu (Brewski Rogers) writes: >How exactly do static column RAMs work? I know you get the first word >in the normal amount of time, and following words from the same column >much quicker, but how MUCH quicker? Technically speaking, the access time goes from about 80ns for normal cycle to around 35ns for the static column cycle. The cycle time goes from around 160ns minimum to 45ns minimum. In A3000 terms, the cycle time goes from 200ns for a normal random memory cycle down to 80ns for a burst cycle. The difference between the actual minimum memory cycle and the cycle you achieve in the system is to be expected, its the allowance for part tolerances, logic between the 68030 and the memory, things like that. >Also, do you have to do anything special to read static column RAMs, or do >they magically figure out that you asked for 4 sequential words? You have to provide a new column address for each of the words. In burst mode, it means that RAMSEY has to count though all combinations of A2 and A3 to run a full burst (starting, as the 68030 requires, with the word actually addressed and wrapping around if necessary to complete the 4 word cycle). >2822 Ganges Bruce (6502 RULES!) Rogers |\ Duck ( 0 0) -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy Wheeeeeeeeeeeeeeee...........