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Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/Documentation/video4linux/radiotrack.txt b/Documentation/video4linux/radiotrack.txt
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+NOTES ON RADIOTRACK CARD CONTROL
+by Stephen M. Benoit (benoits@servicepro.com) Dec 14, 1996
+----------------------------------------------------------------------------
+
+Document version 1.0
+
+ACKNOWLEDGMENTS
+----------------
+This document was made based on 'C' code for Linux from Gideon le Grange
+(legrang@active.co.za or legrang@cs.sun.ac.za) in 1994, and elaborations from
+Frans Brinkman (brinkman@esd.nl) in 1996. The results reported here are from
+experiments that the author performed on his own setup, so your mileage may
+vary... I make no guarantees, claims or warranties to the suitability or
+validity of this information. No other documentation on the AIMS
+Lab (http://www.aimslab.com/) RadioTrack card was made available to the
+author. This document is offered in the hopes that it might help users who
+want to use the RadioTrack card in an environment other than MS Windows.
+
+WHY THIS DOCUMENT?
+------------------
+I have a RadioTrack card from back when I ran an MS-Windows platform. After
+converting to Linux, I found Gideon le Grange's command-line software for
+running the card, and found that it was good! Frans Brinkman made a
+comfortable X-windows interface, and added a scanning feature. For hack
+value, I wanted to see if the tuner could be tuned beyond the usual FM radio
+broadcast band, so I could pick up the audio carriers from North American
+broadcast TV channels, situated just below and above the 87.0-109.0 MHz range.
+I did not get much success, but I learned about programming ioports under
+Linux and gained some insights about the hardware design used for the card.
+
+So, without further delay, here are the details.
+
+
+PHYSICAL DESCRIPTION
+--------------------
+The RadioTrack card is an ISA 8-bit FM radio card. The radio frequency (RF)
+input is simply an antenna lead, and the output is a power audio signal
+available through a miniature phone plug. Its RF frequencies of operation are
+more or less limited from 87.0 to 109.0 MHz (the commercial FM broadcast
+band). Although the registers can be programmed to request frequencies beyond
+these limits, experiments did not give promising results. The variable
+frequency oscillator (VFO) that demodulates the intermediate frequency (IF)
+signal probably has a small range of useful frequencies, and wraps around or
+gets clipped beyond the limits mentioned above.
+
+
+CONTROLLING THE CARD WITH IOPORT
+--------------------------------
+The RadioTrack (base) ioport is configurable for 0x30c or 0x20c. Only one
+ioport seems to be involved. The ioport decoding circuitry must be pretty
+simple, as individual ioport bits are directly matched to specific functions
+(or blocks) of the radio card. This way, many functions can be changed in
+parallel with one write to the ioport. The only feedback available through
+the ioports appears to be the "Stereo Detect" bit.
+
+The bits of the ioport are arranged as follows:
+
+ MSb LSb
++------+------+------+--------+--------+-------+---------+--------+
+| VolA | VolB | ???? | Stereo | Radio | TuneA | TuneB | Tune |
+| (+) | (-) | | Detect | Audio | (bit) | (latch) | Update |
+| | | | Enable | Enable | | | Enable |
++------+------+------+--------+--------+-------+---------+--------+
+
+
+VolA . VolB [AB......]
+-----------
+0 0 : audio mute
+0 1 : volume + (some delay required)
+1 0 : volume - (some delay required)
+1 1 : stay at present volume
+
+Stereo Detect Enable [...S....]
+--------------------
+0 : No Detect
+1 : Detect
+
+ Results available by reading ioport >60 msec after last port write.
+ 0xff ==> no stereo detected, 0xfd ==> stereo detected.
+
+Radio to Audio (path) Enable [....R...]
+----------------------------
+0 : Disable path (silence)
+1 : Enable path (audio produced)
+
+TuneA . TuneB [.....AB.]
+-------------
+0 0 : "zero" bit phase 1
+0 1 : "zero" bit phase 2
+
+1 0 : "one" bit phase 1
+1 1 : "one" bit phase 2
+
+ 24-bit code, where bits = (freq*40) + 10486188.
+ The Most Significant 11 bits must be 1010 xxxx 0x0 to be valid.
+ The bits are shifted in LSb first.
+
+Tune Update Enable [.......T]
+------------------
+0 : Tuner held constant
+1 : Tuner updating in progress
+
+
+PROGRAMMING EXAMPLES
+--------------------
+Default: BASE <-- 0xc8 (current volume, no stereo detect,
+ radio enable, tuner adjust disable)
+
+Card Off: BASE <-- 0x00 (audio mute, no stereo detect,
+ radio disable, tuner adjust disable)
+
+Card On: BASE <-- 0x00 (see "Card Off", clears any unfinished business)
+ BASE <-- 0xc8 (see "Default")
+
+Volume Down: BASE <-- 0x48 (volume down, no stereo detect,
+ radio enable, tuner adjust disable)
+ * wait 10 msec *
+ BASE <-- 0xc8 (see "Default")
+
+Volume Up: BASE <-- 0x88 (volume up, no stereo detect,
+ radio enable, tuner adjust disable)
+ * wait 10 msec *
+ BASE <-- 0xc8 (see "Default")
+
+Check Stereo: BASE <-- 0xd8 (current volume, stereo detect,
+ radio enable, tuner adjust disable)
+ * wait 100 msec *
+ x <-- BASE (read ioport)
+ BASE <-- 0xc8 (see "Default")
+
+ x=0xff ==> "not stereo", x=0xfd ==> "stereo detected"
+
+Set Frequency: code = (freq*40) + 10486188
+ foreach of the 24 bits in code,
+ (from Least to Most Significant):
+ to write a "zero" bit,
+ BASE <-- 0x01 (audio mute, no stereo detect, radio
+ disable, "zero" bit phase 1, tuner adjust)
+ BASE <-- 0x03 (audio mute, no stereo detect, radio
+ disable, "zero" bit phase 2, tuner adjust)
+ to write a "one" bit,
+ BASE <-- 0x05 (audio mute, no stereo detect, radio
+ disable, "one" bit phase 1, tuner adjust)
+ BASE <-- 0x07 (audio mute, no stereo detect, radio
+ disable, "one" bit phase 2, tuner adjust)
+
+----------------------------------------------------------------------------