.\"	$NetBSD: sf2r.4,v 1.6 2020/08/24 19:25:57 ryoon Exp $
.\"	$RuOBSD: sf2r.4,v 1.3 2001/10/26 05:38:44 form Exp $
.\"	$OpenBSD: sf2r.4,v 1.2 2001/12/05 11:27:44 mickey Exp $
.\"
.\" Copyright (c) 2001 Vladimir Popov
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
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.\"    notice, this list of conditions and the following disclaimer.
.\" 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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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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.Dd August 25, 2020
.Dt SF2R 4
.Os
.Sh NAME
.Nm sf2r
.Nd SoundForte RadioLink SF16-FMR2 FM radio device driver
.Sh SYNOPSIS
.Cd option RADIO_TEA5759
.Pp
.Cd "sf2r0  at isa? port 0x384"
.Cd "radio* at sf2r0"
.Sh DESCRIPTION
The
.Nm
driver provides support for the SF16-FMR2 FM radio tuners.
.Pp
The SF16-FMR2 is a stereo FM tuner that allows to tune in the range
87.5 - 108.0 MHz, report signal status on the current frequency, force
audio output to mono, perform hardware signal search, and has an internal
AFC.
.Pp
The SF16-FMR2 cards take only one I/O port.
The I/O port is set by the driver to the value specified in the configuration
file and must be 0x384.
.Pp
Philips Semiconductors released two almost identical chips TEA5757 and
TEA5759.
The TEA5757 is used in FM-standards in which the local oscillator frequency
is above the radio frequency (e.g. European and American standards).
The TEA5759 is the version in which the oscillator frequency is below
the radio frequency (e.g. Japanese standards).
The option
.Va RADIO_TEA5759
changes the algorithm of frequency calculation for the TEA5757 based cards
to conform with the Japanese standards.
.Sh SEE ALSO
.Xr isa 4 ,
.Xr radio 4
.Sh HISTORY
The
.Nm
device driver appeared in
.Ox 3.0
and
.Nx 1.6 .
.Sh AUTHORS
.An -nosplit
The
.Nm
driver was written by
.An Vladimir Popov
and
.An Maxim Tsyplakov.
The man page was written by
.An Vladimir Popov .
.Sh BUGS
MediaForte made two variants of the SF16-FMR2 cards, the first one has
an internal amplifier of the output sound, the second one does not have
such an amplifier.
The current driver supports only the second variant.