90 lines
3.0 KiB
Groff
90 lines
3.0 KiB
Groff
.\" $NetBSD: isv.4,v 1.4 2009/10/19 23:29:40 dyoung Exp $
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.\"
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.\" Copyright (c) 2008 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD
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.\" Foundation by David Young.
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.\"
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.\" Redistribution and use in source and binary forms, with or
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.\" without modification, are permitted provided that the following
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.\" conditions are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above
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.\" copyright notice, this list of conditions and the following
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.\" disclaimer in the documentation and/or other materials
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.\" provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd April 1, 2008
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.Dt isv 4
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.Os
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.Sh NAME
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.Nm isv
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.Nd IDEC Supervision/16 image capture board
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.Sh SYNOPSIS
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.Cd "isv0 at isa? port 0x2f0"
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.Cd "isv0 at isa? port 0x2e0"
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.Cd "isv0 at isa? port 0x3f0"
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.Cd "isv0 at isa? port 0x3e0"
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.Sh DESCRIPTION
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.Pp
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.Nm
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is a driver for the IDEC Supervision/16, an image capture board
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that plugs into a 16-bit ISA bus.
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The IDEC Supervision/16 digitizes an NTSC television signal, storing
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a 512 x 480-pixel, 8-bit grayscale image in its 256kB dynamic RAM array
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every 1/30th of a second.
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The host reads frames from the DRAM using 122881 16-bit I/O reads.
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Reading frames from the Supervision/16 is quite slow:
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after the host reads a 16-bit word from the DRAM, the Supervision/16
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state machine takes approximately 0.5 microseconds to get ready
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for the next read.
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Theoretically, a frame rate of approximately 10 frames per second
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is possible.
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.Nm
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achieves a frame rate of approximately 6 frames per second.
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.Pp
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.Sh SEE ALSO
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.Xr isvctl 8
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.Rs
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.%R Programming the Supervision/16 Image Capture Board
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.%Q IDEC
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.%D circa 1991
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.Re
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.Sh HISTORY
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The
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.Nm
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device first appeared in
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.Nx 5.0 .
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.Sh AUTHORS
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The
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.Nm
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driver was written by
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.An David Young Aq dyoung@NetBSD.org .
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.Sh BUGS
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.Pp
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Synchronizing with the hardware and reading frames from it is very
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CPU-intensive.
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.Pp
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.Nm
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will not detect the capture board if it is not attached to an active
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video source.
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To force
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.Nx
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to detect the capture board at any time, re-scan the ISA bus using,
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e.g.,
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.Ic drvctl Fl r Ar isa0 .
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