[comp.sys.hp] Hewlett Packard Image Scanner

jeremy@perf2.sgi.com (Jeremy Higdon) (05/29/90)

In article <May.27.21.30.32.1990.23246@topaz.rutgers.edu>, 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.  I can send escape codes to the scanner and make it seek, turn 
> the light on, and perform a 'scan test', but I can't seem to _read_ any data 
> _from_ the scanner.  Any commands that are supposed to make the scanner 
> send out data just seem to do nothing.  Does HP use some strange kind of 
> handshaking in their scanner?  (I'm using the HP developer manual for the
> escape codes, but there is no mention of the hardware interface.)  All the
> other machines in our lab (HP PC's and Mac IIcx's) all use HP manufactured
> interfaces, so there is no problem communicating with the scanner.
> 

Does the Amiga parallel device support data input?  Most parallel devices
don't.  This is why the ScanJet for the IBM PC came with a parallel board.

valentin@cbmvax.commodore.com (Valentin Pepelea) (05/31/90)

In article <May.27.21.30.32.1990.23246@topaz.rutgers.edu>
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
-- 
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may distroy a statue,  but they cannot     Phone:   (215) 431-9327
kill a god."                               UseNet:  cbmvax!valentin@uunet.uu.net
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Classic_-_Concepts@cup.portal.com (06/02/90)

Does anyone have any experience, advice re: the Mirror brand 300 dpi
full page scanner?  It seems to be substantially cheaper (about $300) than
other apparently similar scanners.  I'm referring to the gray scale scanner
in the $700 ball park.  Information, suggestions appreciate.   - LH