davidb@inmos.co.uk (David Boreham) (12/18/90)
In article <1178@shakti.ncst.ernet.in> shri@ncst.ernet.in (H.Shrikumar) writes: >In article <AGLEW.90Dec9184818@lasso.crhc.uiuc.edu> > aglew@crhc.uiuc.edu (Andy Glew) writes: >> >>The likely successor to VME is VME-64. It's simple, fast, and >>available now. The likely successor to VME-64, if there is a lineal >>successor, will probably involve noticing that there are extra pins on >>most VME boards second connector... > > I was under the (evidently wrong) impression that VME-64 uses those pins! >Could you drop in a brief note on the pinout please ? VME-64 (which was first proposed by Performance Technologies) works on the principle that, during block transfers (BLT transfers), the address bus carries no useful signals after the initial address-phase. Consequently these 31 lines are free to carry data during the data-transfer-phase. Can't remember where the other bit comes from, but anyway, this means that during the data-transfer cycles of a BLT operation, it is possible to move 64-bits at a time, rather than the 32-bits possible with basic VMEbus. David Boreham, INMOS Limited | mail(uk): davidb@inmos.co.uk or ukc!inmos!davidb Bristol, England | (us): uunet!inmos.com!davidb +44 454 616616 ex 547 | Internet: davidb@inmos.com
daveh@cbmvax.commodore.com (Dave Haynie) (01/08/91)
In article <13180@ganymede.inmos.co.uk> davidb@inmos.co.uk (David Boreham) writes: > shri@ncst.ernet.in (H.Shrikumar) writes: >> aglew@crhc.uiuc.edu (Andy Glew) writes: >> I was under the (evidently wrong) impression that VME-64 uses those pins! >Can't remember where the other bit comes from, but anyway, this means >that during the data-transfer cycles of a BLT operation, it is possible >to move 64-bits at a time, rather than the 32-bits possible with basic VMEbus. Which goes to demonstrate the principle that just about any non-multiplexed N-Bit wide bus is just a multiplexed N*2-Bit wide bus that hasn't been enhanced yet. VME64 is the latest example. We did this with the 16 bit Amiga bus, IBM at least specified the same idea with the non-multiplexed 32 bit MCA bus that mutates into a multiplexed 64 bit bus, and I'm sure there are others (is that how STD32 works?). I guess MIT and TI leapfrogged the inevitable by stating out multiplexed in the first place with NuBus :-)... >David Boreham, INMOS Limited | mail(uk): davidb@inmos.co.uk or ukc!inmos!davidb -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "Don't worry, 'bout a thing. 'Cause every little thing, gonna be alright" -Bob Marley