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.