$OpenBSD: radio.4,v 1.5 2002/01/07 18:37:45 mickey Exp $
Copyright (c) 2001 Vladimir Popov
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.Dd October 20, 2001 .Dt RADIO 4 .Os .Sh NAME .Nm radio .Nd device-independent radio driver layer .Sh SYNOPSIS
p .Cd "radio* at az0" .Cd "radio* at mr0" .Cd "radio* at rt0" .Cd "radio* at rtii0" .Cd "radio* at sf2r0" .Cd "radio* at sf4r0"
p .Fd #include <sys/types.h> .Fd #include <sys/ioctl.h> .Fd #include <sys/radioio.h> .Sh DESCRIPTION The .Nm driver provides support for various FM radio cards. It provides an uniform programming interface layer above different underlying radio hardware drivers.
p For radio tuner controlling there is a single device file available:
p The following .Xr ioctl 2 commands are supported:
p l -tag -width indent -compact t Dv RIOCSSRCH (int) This command assumes that a signal search is required and gives direction of search to the driver - 0 to search down and any non-zero value to search up. t Dv RIOCSINFO (struct radio_info) t Dv RIOCGINFO (struct radio_info) Get or set the current hardware device information into the struct radio_info structure. d -literal struct radio_info { int mute; int volume; int stereo; int rfreq; /* reference frequency */ int lock; /* locking field strength */ u_int32_t freq; /* in kHz */ u_int32_t caps; /* card capabilities */ #define RADIO_CAPS_DETECT_STEREO (1<<0) #define RADIO_CAPS_DETECT_SIGNAL (1<<1) #define RADIO_CAPS_SET_MONO (1<<2) #define RADIO_CAPS_HW_SEARCH (1<<3) #define RADIO_CAPS_HW_AFC (1<<4) #define RADIO_CAPS_REFERENCE_FREQ (1<<5) #define RADIO_CAPS_LOCK_SENSITIVITY (1<<6) #define RADIO_CARD_TYPE (0xFF<<16) u_int32_t info; #define RADIO_INFO_STEREO (1<<0) #define RADIO_INFO_SIGNAL (1<<1) }; .Ed
p The .Va mute field is a boolean.
p The .Va volume field holds the card volume information and can be at most 255.
p The .Va stereo field is a boolean.
p The .Va rfreq holds information about the card reference frequency (not all cards support this feature).
p The .Va lock field holds information about the card locking field strength during an automatic search for cards that support this feature.
p The .Va freq field is the frequency in kHz the card is tuned to.
p The .Va caps field is read-only and describes the card capabilities. The capabilities can have following values: l -tag -width indent -compact t Dv RADIO_CAPS_DETECT_STEREO The device can determine is it tuned to a stereo signal. t Dv RADIO_CAPS_DETECT_SIGNAL The device can determine is it tuned or not. t Dv RADIO_CAPS_SET_MONO The device capable to forcible set its output to mono. t Dv RADIO_CAPS_HW_SEARCH The device can do hardware search. t Dv RADIO_CAPS_HW_AFC The device has an internal hardware automatic frequency control. t Dv RADIO_CAPS_REFERENCE_FREQ The device allow to change the reference frequency of a received signal. t Dv RADIO_CAPS_LOCK_SENSITIVITY The device allow to change the station lock sensitivity used during search operation. t Dv RADIO_CAPS_CARD_TYPE Some cards have several different incarnations. This allow to determine the variant of the card. Currently not used. .El
p The .Va info field is read-only and describes current state of the card - tuned/not tuned, stereo signal/mono signal. l -tag -width indent -compact t Dv RADIO_INFO_SIGNAL Informs whether the device receives a valid signal or noise. t Dv RADIO_INFO_STEREO Informs whether the device receives a stereo or mono signal. .El .El .Sh CHIPSETS
p LM700x is a frequency synthesizer IC. The LM700x is programmed through a 24-bit write-only shift register. The first 14 bits are frequency data. The next 2 bits are LSI test bits, and should always be zero. The next 4 bits are band data and time base data. They can be programmed to force a given reference frequency, or they can be set to zero and the next 3 bits can be used to set the reference frequency. The final bit selects the divider selection, which is 1 for FM and 0 for AM. The LM700x chips are used in .Xr az 4 and .Xr rt 4 cards.
p The TEA5757; TEA5759 is a 44-pin integrated AM/FM stereo radio circuit. The radio part is based on the TEA5712. 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). To conform with the Japanese standards it is needed to set the flags least significant bit to 1. The TEA5757; TEA5759 has a 25-bit read-write shift register. The TEA5757 chips are used in .Xr mr 4 , .Xr rtii 4 , .Xr sf2r 4 and .Xr sf4r 4 cards. .Sh FILES l -tag -width /dev/radio -compact t Pa /dev/radio .El .Sh SEE ALSO .Xr ioctl 2 , .Xr az 4 , .Xr mr 4 , .Xr rt 4 , .Xr rtii 4 , .Xr sf2r 4 , .Xr sf4r 4 , .Xr radio 9 .Sh BUGS You can have only one card of the same type. For example, if you have two aztech FM tuners, the first card with jumper set to port 0x358 and the second one - to 0x350, you can use only one aztech card (in the kernel, that is) either with port 0x350 or 0x358. Don't even try to compile support for the second card into the kernel. .Sh AUTHORS The .Nm driver was written by .An Vladimir Popov Aq jumbo@narod.ru and .An Maxim Tsyplakov Aq tm@oganer.net . The man page was written by .An Vladimir Popov Aq jumbo@narod.ru . .Sh HISTORY The .Nm device driver appeared in .Ox 3.0 .