Xref: utzoo comp.sys.amiga.tech:12315 comp.sys.amiga.hardware:1989 comp.sys.ibm.pc:51556 comp.sys.hp:5205 comp.graphics:11741 comp.periphs:2914 Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!cbmvax!valentin From: valentin@cbmvax.commodore.com (Valentin Pepelea) Newsgroups: comp.sys.amiga.tech,comp.sys.amiga.hardware,comp.sys.ibm.pc,comp.sys.hp,comp.graphics,comp.periphs Subject: Re: Hewlett Packard Image Scanner Keywords: ScanJet, Amiga 2000, parallel interface problems Message-ID: <11969@cbmvax.commodore.com> Date: 30 May 90 17:57:43 GMT References: Reply-To: valentin@cbmvax (Valentin Pepelea) Distribution: inet Organization: Commodore, West Chester, PA Lines: 20 In article armhold@topaz.rutgers.edu (George Armhold) writes: > > Our lab owns an HP Scanjet Image Scanner. I'm trying to write a driver for > for our Amiga 2000 using the Amiga's parallel.device. I can successfully > execute any commands that don't require the scanner to send any data > back to the Amiga. However, any commands that are supposed to return any > data do not work. Unlike the serial device, the parallel device is not bidirectional. Although you can both read and write through the parallel device, a CMD_READ I/O request has to be sent *before* the remote starts writing. If the remote starts writing first, you risk hanging up the device. Valentin -- The Goddess of democracy? "The tyrants Name: Valentin Pepelea may distroy a statue, but they cannot Phone: (215) 431-9327 kill a god." UseNet: cbmvax!valentin@uunet.uu.net - Ancient Chinese Proverb Claimer: I not Commodore spokesman be