NetBSD/share/man/man4/man4.vax/ad.4

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.\" $NetBSD: ad.4,v 1.6 1999/12/15 23:44:54 abs Exp $
.\"
.\" Copyright (c) 1983, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
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.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
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.\" 3. All advertising materials mentioning features or use of this software
.\" must display the following acknowledgement:
.\" This product includes software developed by the University of
.\" California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\"
.\" from: @(#)ad.4 8.1 (Berkeley) 6/5/93
.\"
.Dd June 5, 1993
.Dt AD 4 vax
.Os
.Sh NAME
.Nm ad
.Nd Data Translation A/D converter
.Sh SYNOPSIS
.Cd "ad0 at uba0 csr 0170400 vector adintr"
.Sh DESCRIPTION
The
.Nm \&ad
driver
provides an interface to the Data Translation A/D converter.
This is
.Em not
a real-time driver, but merely allows
the user process to sample the board's channels one at a time.
Each minor device selects a different
.Tn A/D
board.
.Pp
The driver communicates to a user process by means of
.Xr ioctl 2 Ns s.
The
.Dv AD_CHAN
.Xr ioctl
selects which channel of the board to read.
For example,
.Bd -literal -offset indent
chan = 5;
ioctl(fd, AD_CHAN, &chan);
.Ed
.Pp
selects channel 5.
The
.Dv AD_READ
.Xr ioctl 2
actually reads the data and returns it to the user
process.
An example is
.Bd -literal -offset indent
ioctl(fd, AD_READ, &data);
.Ed
.Sh FILES
.Bl -tag -width /dev/adx -compact
.It Pa /dev/ad
.El
.Sh DIAGNOSTICS
None.
.Sh HISTORY
The
.Nm
driver appeared in
.Bx 4.1 .