1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)ad.4 8.1 (Berkeley) 06/05/93 7.\" 8.Dd 9.Dt AD 4 vax 10.Os BSD 4.2 11.Sh NAME 12.Nm ad 13.Nd Data Translation A/D converter 14.Sh SYNOPSIS 15.Cd "device ad0 at uba0 csr 0170400 vector adintr" 16.Sh DESCRIPTION 17The 18.Nm \&ad 19driver 20provides an interface to the Data Translation A/D converter. 21This is 22.Em not 23a real-time driver, but merely allows 24the user process to sample the board's channels one at a time. 25Each minor device selects a different 26.Tn A/D 27board. 28.Pp 29The driver communicates to a user process by means of 30.Xr ioctl 2 Ns s. 31The 32.Dv AD_CHAN 33.Xr ioctl 34selects which channel of the board to read. 35For example, 36.Bd -literal -offset indent 37chan = 5; 38ioctl(fd, AD_CHAN, &chan); 39.Ed 40.Pp 41selects channel 5. 42The 43.Dv AD_READ 44.Xr ioctl 2 45actually reads the data and returns it to the user 46process. 47An example is 48.Bd -literal -offset indent 49ioctl(fd, AD_READ, &data); 50.Ed 51.Sh FILES 52.Bl -tag -width /dev/adx -compact 53.It Pa /dev/ad 54.El 55.Sh DIAGNOSTICS 56None. 57.Sh HISTORY 58The 59.Nm 60driver appeared in 61.Bx 4.1 . 62