Date: Wed, 25 Jun 1997 14:59:54 +0930 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: atrens@nortel.ca (Andrew Atrens) Cc: hackers@FreeBSD.ORG Subject: Re: newbie device driver question. Message-ID: <199706250529.OAA28847@genesis.atrad.adelaide.edu.au> In-Reply-To: <199706250502.WAA00875@hub.freebsd.org> from Andrew Atrens at "Jun 25, 97 01:00:00 am"
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Andrew Atrens stands accused of saying: > > Now, Logitech appears to have two models to choose from. The newest model > connects via parallel port and communicates via a proprietary protocol with > the PC. The second, older variety has its own ISA card. A partially complete > (alpha quality) linux driver already exists for this beastie. Sounds like the latter would be easiest to work with. > So, to get to the point, I suppose the older model ( the one with > the proprietary ISA card ), would require a (standard) ISA device > driver much like what one of Julian's scripts would produce. BUT the > newer model, requiring only a parallel port connection, would that > need an ISA dev driver, or else a `pseudo device' driver? Or perhaps > just a simple userland program? As I said, this is a *newbie* > question. It depends somewhat on the protocol. If you wanted just to hack at it, you could disable your parallel port driver and use the /dev/io method for talking to the scanner; this _might_ be fast enough. > Regardless, I think I've resigned myself to buying the older model, since > I'm not sure how to begin to reverse-engineer the newer's port protocol. If the protocol is undocumented, you'd have to sit down with a logic analyser and try to work it out. Yuck. The parallel port infrastructure is one of the things I'd like to take a crack at, in that the current arrangement is pretty awful. Having said that, I've found myself swimming in datasheets and documentation wrt. the various "enhanced" parallel port modes trying to work out how to do this right. I still need a copy of ieee 1284 if someone has one... -- ]] Mike Smith, Software Engineer msmith@gsoft.com.au [[ ]] Genesis Software genesis@gsoft.com.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control. (ph) +61-8-8267-3493 [[ ]] Unix hardware collector. "Where are your PEZ?" The Tick [[
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