smith@evax.uta.edu (01/24/91)
Have you interfaced a SCSI chip? I would like to interface a Single chip MCU to a SCSI hard drive. To save on $$ I would like to *not* use a SCSI controller chip in the commercial design. Is this practical? Can SCSI work in an asynchronous mode? Where can I find a *simple* explanation of the SCSI interface? If I must use a SCSI controller chip, what chip would you suggest? Where can I get a cheap chip, and do you have any source code which shows the sequence of commands to read/write/format etc... I would also be interested in any info on other Drive interfaces such as MFM (506), RLL, ESDI, IDE. I will put together what I already have, what is sent to me, and what I make up in a file to either post or mail directly to you depending on the size....thanks in advance. Jeff Smith
wgstuken@faui4n.informatik.uni-erlangen.de (Wolfgang Stukenbrock (Dipl. Zugangssystem Inf4)) (01/24/91)
smith@evax.uta.edu writes: >...? I would like to interface a Single chip MCU to >a SCSI hard drive. ... Is this practical? Yes, it is practical. >Can SCSI work in an asynchronous mode? You wouldn't reach full speed (asynchronous) and will run into trubble, if you like to use synchronous, But it will work. SCSI controller-chips does nothing else as you wil do with the MCU. >Where can I find a *simple* explanation of the SCSI interface? ... >Where can I get a cheap chip, and do you have any source code ... Look at SCSI specifications. There you find the SCSI-commands, thats all you need. It's easy to write it yourself! Wolfgang
gerry@zds-ux.UUCP (Gerry Gleason) (01/25/91)
In article <wgstuken.664715154@faui4n> wgstuken@faui4n.informatik.uni-erlangen.de (Wolfgang Stukenbrock (Dipl. Zugangssystem Inf4)) writes: >smith@evax.uta.edu writes: >>Can SCSI work in an asynchronous mode? >You wouldn't reach full speed (asynchronous) and will >run into trubble, if you like to use synchronous, But it will work. >SCSI controller-chips does nothing else as you wil do with the MCU. Actually, most systems probably do not use synchronous mode at all, and some drives may not have this capability. All interfaces must be able to to asynchronous since this handshake mode is used for all non-data transfers over SCSI. Also, someone here has measured asynchronous transfers burst at nearly the 5.0 MB/sec synchronous rate. This was on a short cable, so I would guess that has something to do with getting high asynchronous rates. Gerry Gleason
mjacob@wonky.Eng.Sun.COM (Matt Jacob) (01/29/91)
Emulex has claimed to be able to do up to ~8-10mb/s async. mode (in the lab). This probably implies bus lengths on the order of millimeters. -matt