isv(4) - NetBSD Manual Pages

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ISV(4)                  NetBSD 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.  Theoretically, 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.

NetBSD 9.2                       April 1, 2008                      NetBSD 9.2