150 lines
5.9 KiB
Groff
150 lines
5.9 KiB
Groff
.\"
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.\" Copyright (c) 1998 Scottibox
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.\" All rights reserved.
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.\"
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer
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.\" in this position and unchanged.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. The name of the author may not be used to endorse or promote products
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.\" derived from this software without specific prior written permission
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" Industrial Computer Source model AIO8-P
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.\" 8 channel, moderate speed analog to digital converter board with
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.\" 128 channel MUX capability via daisy-chained AT-16P units
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.\" alog.c, character device driver, last revised January 6 1998
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.\" See http://www.scottibox.com
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.\" http://www.indcompsrc.com/products/data/html/aio8g-p.html
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.\" http://www.indcompsrc.com/products/data/html/at16-p.html
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.\"
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.\" Written by: Jamil J. Weatherbee <jamil@scottibox.com>
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.\"
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.\"
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.Dd January 6, 1998
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.Dt ALOG 4 i386
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.Os FreeBSD
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.Sh NAME
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.Nm alog
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.Nd
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Industrial Computer Source AIO8-P driver
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.Sh SYNOPSIS
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.Cd "device alog0 at isa? port 0x260 tty irq 5"
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.Sh DESCRIPTION
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This driver supports the Industrial Computer Source \fIAIO8-P 8-Channel
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12-Bit Analog Input board\fP.
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.Pp
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This board provides 8 12 bit, single-ended analog input ports.
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The driver also directly provides support for up to 8 daisy chained
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\fIAT16-P Programmable Analog Multiplexers with 16 Differential Inputs\fP.
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This makes it possible to sample up to 128 differential channels with a single
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interface board.
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Use of at least one \fIAT16-P\fP is highly recommended as the \fIAIO8-P\fP
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offers no signal conditioning options and only operates in a -5 to +5 Volt
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input range. However, if you wish to use the \fIAIO8-P\fP standalone,
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insert the following into your kernel
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.Xr config 8
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file:
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.Bd -literal -offset indent
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options ALOG_CHANNELS=8
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.Ed
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.Pp
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Selection of the input port is through the minor number:
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.Pp
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.Bd -literal -offset indent
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The 8 bit minor number format is UCCCCMMM, where
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U: board unit (0-1)
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CCCC: external multiplexer channel (0-15) (on AT-16P units)
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MMM: internal multiplexer channel (0-7) (on AIO8-P card)
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.Ed
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.Pp
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.Xr devfs 5
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device node names are of the form: alog[0-1][a-p][0-7]
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.Pp
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.Sh IOCTL
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The following
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.Xr ioctl 2
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calls apply to
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.Nm
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devices. Their declaration can be found in the header files
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.Pa <sys/alogio.h>
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and
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.Pa <sys/dataacq.h>
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.Bl -tag -width AD_MICRO_PERIOD_SET
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.It Dv AD_MICRO_PERIOD_SET
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Takes a pointer to a long argument specifying the number of microseconds
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between samples. Half of this is used as the external multiplexer
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settling time and the other half as conversion time.
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.It Dv AD_MICRO_PERIOD_GET
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Takes a pointer to a long argument and returns the current number of
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microseconds between samples.
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.It Dv AD_NCHANS_GET
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Takes a pointer to an integer and returns the number of channels the board
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supports. This should be 8 for a standalone \fIAIO8-P\fP or 128 for any
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other setup.
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.It Dv AD_FIFOSIZE_GET
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Takes a pointer to an integer and returns the size of the fifo in
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entries. The compile time option ALOG_FIFOSIZE is by default set to 64.
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.It Dv AD_FIFO_TRIGGER_GET
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Takes a pointer to an integer and returns the minimum number of entries a
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fifo must contain to cause
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.Xr poll 2
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to return. This by default is set to 1.
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.It Dv AD_FIFO_TRIGGER_SET
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Takes a pointer to an integer specifying the minimum number of entries a
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fifo must contain to cause
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.Xr poll 2
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to return.
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.It Dv AD_START
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Starts the clocked accumulation of sample values into a channel's driver fifo.
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When a channel is first opened its software fifo is initialized in the
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stopped state. This is to prevent high sample clocks from overrunning the
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fifos before the user is ready to read from the channel. The driver
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automatically performs an AD_START when the user issues the first read,
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except for channels opened with the O_NONBLOCK flag which must explicitly
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have an AD_START issued.
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.It Dv AD_STOP
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Stops the clocked accumulation of sample values into a channel's driver fifo.
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.Sh BUGS
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On the \fIAIO8-P\fP, interrupt driven conversion (the only type
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supported by the
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.Nm
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driver) is facilitated through 8253 timer #2. In order for interrupts to
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be generated you must connect line 6 to line 24 (counter 2 output to
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interrupt input) and line 23 to line 29 (counter 2 gate to +5VDC).
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The design of the \fIAIO8-P\fP precludes the use of programmable
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gain control.
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.Pp
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Use the combination of non-blocking i/o,
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.Xr poll 2
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and a custom fifo trigger
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wherever possible, especially with large numbers of open channels.
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Using this method, multichannel sample rates as high as 16,000 samples/sec
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have been observed.
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.Pp
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Sample rates lower than 32 Hz are not supported.
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.Sh SEE ALSO
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.Bd -literal
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http://www.scottibox.com
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http://www.indcompsrc.com/products/data/html/aio8g-p.html
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http://www.indcompsrc.com/products/data/html/at16-p.html
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.Ed
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.Sh AUTHORS
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.An Jamil J. Weatherbee Aq jamil@scottibox.com
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