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diff --git a/Documentation/video4linux/radiotrack.txt b/Documentation/video4linux/radiotrack.txt new file mode 100644 index 000000000000..2b75345f13e3 --- /dev/null +++ b/Documentation/video4linux/radiotrack.txt @@ -0,0 +1,147 @@ +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) + +---------------------------------------------------------------------------- |