ISV(4)							   BSD Kernel Interfaces Manual 						    ISV(4)

NAME

     isv -- IDEC Supervision/16 image capture board

SYNOPSIS

     isv0 at isa? port 0x2f0
     isv0 at isa? port 0x2e0
     isv0 at isa? port 0x3f0
     isv0 at isa? port 0x3e0

DESCRIPTION

     isv 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.  Theoreti-
     cally, a frame rate of approximately 10 frames per second is possible.  isv achieves a frame rate of approximately 6 frames per second.

SEE ALSO

     Programming the Supervision/16 Image Capture Board, IDEC, circa 1991.

HISTORY

     The isv device first appeared in NetBSD 5.0.

AUTHORS

     The isv driver was written by David Young <dyoung@NetBSD.org>.

BUGS

     Synchronizing with the hardware and reading frames from it is very CPU-intensive.

     isv will not detect the capture board if it is not attached to an active video source.  To force NetBSD to detect the capture board at any
     time, re-scan the ISA bus using, e.g., drvctl -r isa0.

BSD
								   April 1, 2008							       BSD