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1 NOTES ON RADIOTRACK CARD CONTROL 2 by Stephen M. Benoit (benoits@servicepro.com) Dec 14, 1996 3 ---------------------------------------------------------------------------- 4 5 Document version 1.0 6 7 ACKNOWLEDGMENTS 8 ---------------- 9 This document was made based on 'C' code for Linux from Gideon le Grange 10 (legrang@active.co.za or legrang@cs.sun.ac.za) in 1994, and elaborations from 11 Frans Brinkman (brinkman@esd.nl) in 1996. The results reported here are from 12 experiments that the author performed on his own setup, so your mileage may 13 vary... I make no guarantees, claims or warranties to the suitability or 14 validity of this information. No other documentation on the AIMS 15 Lab (http://www.aimslab.com/) RadioTrack card was made available to the 16 author. This document is offered in the hopes that it might help users who 17 want to use the RadioTrack card in an environment other than MS Windows. 18 19 WHY THIS DOCUMENT? 20 ------------------ 21 I have a RadioTrack card from back when I ran an MS-Windows platform. After 22 converting to Linux, I found Gideon le Grange's command-line software for 23 running the card, and found that it was good! Frans Brinkman made a 24 comfortable X-windows interface, and added a scanning feature. For hack 25 value, I wanted to see if the tuner could be tuned beyond the usual FM radio 26 broadcast band, so I could pick up the audio carriers from North American 27 broadcast TV channels, situated just below and above the 87.0-109.0 MHz range. 28 I did not get much success, but I learned about programming ioports under 29 Linux and gained some insights about the hardware design used for the card. 30 31 So, without further delay, here are the details. 32 33 34 PHYSICAL DESCRIPTION 35 -------------------- 36 The RadioTrack card is an ISA 8-bit FM radio card. The radio frequency (RF) 37 input is simply an antenna lead, and the output is a power audio signal 38 available through a miniature phone plug. Its RF frequencies of operation are 39 more or less limited from 87.0 to 109.0 MHz (the commercial FM broadcast 40 band). Although the registers can be programmed to request frequencies beyond 41 these limits, experiments did not give promising results. The variable 42 frequency oscillator (VFO) that demodulates the intermediate frequency (IF) 43 signal probably has a small range of useful frequencies, and wraps around or 44 gets clipped beyond the limits mentioned above. 45 46 47 CONTROLLING THE CARD WITH IOPORT 48 -------------------------------- 49 The RadioTrack (base) ioport is configurable for 0x30c or 0x20c. Only one 50 ioport seems to be involved. The ioport decoding circuitry must be pretty 51 simple, as individual ioport bits are directly matched to specific functions 52 (or blocks) of the radio card. This way, many functions can be changed in 53 parallel with one write to the ioport. The only feedback available through 54 the ioports appears to be the "Stereo Detect" bit. 55 56 The bits of the ioport are arranged as follows: 57 58 MSb LSb 59 +------+------+------+--------+--------+-------+---------+--------+ 60 | VolA | VolB | ???? | Stereo | Radio | TuneA | TuneB | Tune | 61 | (+) | (-) | | Detect | Audio | (bit) | (latch) | Update | 62 | | | | Enable | Enable | | | Enable | 63 +------+------+------+--------+--------+-------+---------+--------+ 64 65 66 VolA . VolB [AB......] 67 ----------- 68 0 0 : audio mute 69 0 1 : volume + (some delay required) 70 1 0 : volume - (some delay required) 71 1 1 : stay at present volume 72 73 Stereo Detect Enable [...S....] 74 -------------------- 75 0 : No Detect 76 1 : Detect 77 78 Results available by reading ioport >60 msec after last port write. 79 0xff ==> no stereo detected, 0xfd ==> stereo detected. 80 81 Radio to Audio (path) Enable [....R...] 82 ---------------------------- 83 0 : Disable path (silence) 84 1 : Enable path (audio produced) 85 86 TuneA . TuneB [.....AB.] 87 ------------- 88 0 0 : "zero" bit phase 1 89 0 1 : "zero" bit phase 2 90 91 1 0 : "one" bit phase 1 92 1 1 : "one" bit phase 2 93 94 24-bit code, where bits = (freq*40) + 10486188. 95 The Most Significant 11 bits must be 1010 xxxx 0x0 to be valid. 96 The bits are shifted in LSb first. 97 98 Tune Update Enable [.......T] 99 ------------------ 100 0 : Tuner held constant 101 1 : Tuner updating in progress 102 103 104 PROGRAMMING EXAMPLES 105 -------------------- 106 Default: BASE <-- 0xc8 (current volume, no stereo detect, 107 radio enable, tuner adjust disable) 108 109 Card Off: BASE <-- 0x00 (audio mute, no stereo detect, 110 radio disable, tuner adjust disable) 111 112 Card On: BASE <-- 0x00 (see "Card Off", clears any unfinished business) 113 BASE <-- 0xc8 (see "Default") 114 115 Volume Down: BASE <-- 0x48 (volume down, no stereo detect, 116 radio enable, tuner adjust disable) 117 * wait 10 msec * 118 BASE <-- 0xc8 (see "Default") 119 120 Volume Up: BASE <-- 0x88 (volume up, no stereo detect, 121 radio enable, tuner adjust disable) 122 * wait 10 msec * 123 BASE <-- 0xc8 (see "Default") 124 125 Check Stereo: BASE <-- 0xd8 (current volume, stereo detect, 126 radio enable, tuner adjust disable) 127 * wait 100 msec * 128 x <-- BASE (read ioport) 129 BASE <-- 0xc8 (see "Default") 130 131 x=0xff ==> "not stereo", x=0xfd ==> "stereo detected" 132 133 Set Frequency: code = (freq*40) + 10486188 134 foreach of the 24 bits in code, 135 (from Least to Most Significant): 136 to write a "zero" bit, 137 BASE <-- 0x01 (audio mute, no stereo detect, radio 138 disable, "zero" bit phase 1, tuner adjust) 139 BASE <-- 0x03 (audio mute, no stereo detect, radio 140 disable, "zero" bit phase 2, tuner adjust) 141 to write a "one" bit, 142 BASE <-- 0x05 (audio mute, no stereo detect, radio 143 disable, "one" bit phase 1, tuner adjust) 144 BASE <-- 0x07 (audio mute, no stereo detect, radio 145 disable, "one" bit phase 2, tuner adjust) 146 147 ----------------------------------------------------------------------------