NetBSD-5.0.2/share/man/man4/isv.4

.\"	$NetBSD: isv.4,v 1.1 2008/04/02 01:34:36 dyoung Exp $
.\"
.\" Redistribution and use in source and binary forms, with or
.\" without modification, are permitted provided that the following
.\" conditions are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above
.\"    copyright notice, this list of conditions and the following
.\"    disclaimer in the documentation and/or other materials
.\"    provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this
.\"    software must display the following acknowledgement:
.\"        This product includes software developed by the NetBSD
.\"        Foundation, Inc. and its contributors.
.\" 4. Neither the name of The NetBSD Foundation nor the names of
.\"    its contributors may be used to endorse or promote products
.\"    derived from this software without specific prior written
.\"    permission.
.\"
.Dd April 1, 2008
.Dt isv 4
.Os
.Sh NAME
.Nm isv
.Nd IDEC Supervision/16 image capture board
.Sh SYNOPSIS
.Cd "isv0 at isa? port 0x2f0"
.Cd "isv0 at isa? port 0x2e0"
.Cd "isv0 at isa? port 0x3f0"
.Cd "isv0 at isa? port 0x3e0"
.Sh DESCRIPTION
.Pp
.Nm
is a driver for the IDEC Supervision/16, an image capture board
that plugs into a 16-bit ISA bus.
The IDEC Supervision/16 digitizes an NTSC television signal, storing
a 512 x 480-pixel, 8-bit grayscale image in its 256kB dynamic RAM array
every 1/30th of a second.
The host reads frames from the DRAM using 122881 16-bit I/O reads.
Reading frames from the Supervision/16 is quite slow:
after the host reads a 16-bit word from the DRAM, the Supervision/16
state machine takes approximately 0.5 microseconds to get ready
for the next read.
Theoretically, a frame rate of approximately 10 frames per second
is possible.
.Nm
achieves a frame rate of approximately 6 frames per second.
.Pp
.Sh SEE ALSO
.Xr isvctl 8
.Rs
.%R Programming the Supervision/16 Image Capture Board
.%Q IDEC
.%D circa 1991
.Re
.Sh HISTORY
The
.Nm
device first appeared in
.Nx 5.0 .
.Sh AUTHORS
The
.Nm
driver was written by
.An David Young Aq dyoung@NetBSD.org .
.Sh BUGS
.Pp
Synchronizing with the hardware and reading frames from it is very
CPU-intensive.
.Pp
.Nm
will not detect the capture board if it is not attached to an active
video source.
To force
.Nx
to detect the capture board at any time, re-scan the ISA bus using,
e.g.,
.Ic drvctl Fl r Ar isa0 .