radiotrack.rst (6297B)
1.. SPDX-License-Identifier: GPL-2.0 2 3The Radiotrack radio driver 4=========================== 5 6Author: Stephen M. Benoit <benoits@servicepro.com> 7 8Date: Dec 14, 1996 9 10ACKNOWLEDGMENTS 11---------------- 12 13This document was made based on 'C' code for Linux from Gideon le Grange 14(legrang@active.co.za or legrang@cs.sun.ac.za) in 1994, and elaborations from 15Frans Brinkman (brinkman@esd.nl) in 1996. The results reported here are from 16experiments that the author performed on his own setup, so your mileage may 17vary... I make no guarantees, claims or warranties to the suitability or 18validity of this information. No other documentation on the AIMS 19Lab (http://www.aimslab.com/) RadioTrack card was made available to the 20author. This document is offered in the hopes that it might help users who 21want to use the RadioTrack card in an environment other than MS Windows. 22 23WHY THIS DOCUMENT? 24------------------ 25 26I have a RadioTrack card from back when I ran an MS-Windows platform. After 27converting to Linux, I found Gideon le Grange's command-line software for 28running the card, and found that it was good! Frans Brinkman made a 29comfortable X-windows interface, and added a scanning feature. For hack 30value, I wanted to see if the tuner could be tuned beyond the usual FM radio 31broadcast band, so I could pick up the audio carriers from North American 32broadcast TV channels, situated just below and above the 87.0-109.0 MHz range. 33I did not get much success, but I learned about programming ioports under 34Linux and gained some insights about the hardware design used for the card. 35 36So, without further delay, here are the details. 37 38 39PHYSICAL DESCRIPTION 40-------------------- 41 42The RadioTrack card is an ISA 8-bit FM radio card. The radio frequency (RF) 43input is simply an antenna lead, and the output is a power audio signal 44available through a miniature phone plug. Its RF frequencies of operation are 45more or less limited from 87.0 to 109.0 MHz (the commercial FM broadcast 46band). Although the registers can be programmed to request frequencies beyond 47these limits, experiments did not give promising results. The variable 48frequency oscillator (VFO) that demodulates the intermediate frequency (IF) 49signal probably has a small range of useful frequencies, and wraps around or 50gets clipped beyond the limits mentioned above. 51 52 53CONTROLLING THE CARD WITH IOPORT 54-------------------------------- 55 56The RadioTrack (base) ioport is configurable for 0x30c or 0x20c. Only one 57ioport seems to be involved. The ioport decoding circuitry must be pretty 58simple, as individual ioport bits are directly matched to specific functions 59(or blocks) of the radio card. This way, many functions can be changed in 60parallel with one write to the ioport. The only feedback available through 61the ioports appears to be the "Stereo Detect" bit. 62 63The bits of the ioport are arranged as follows: 64 65.. code-block:: none 66 67 MSb LSb 68 +------+------+------+--------+--------+-------+---------+--------+ 69 | VolA | VolB | ???? | Stereo | Radio | TuneA | TuneB | Tune | 70 | (+) | (-) | | Detect | Audio | (bit) | (latch) | Update | 71 | | | | Enable | Enable | | | Enable | 72 +------+------+------+--------+--------+-------+---------+--------+ 73 74 75==== ==== ================================= 76VolA VolB Description 77==== ==== ================================= 780 0 audio mute 790 1 volume + (some delay required) 801 0 volume - (some delay required) 811 1 stay at present volume 82==== ==== ================================= 83 84==================== =========== 85Stereo Detect Enable Description 86==================== =========== 870 No Detect 881 Detect 89==================== =========== 90 91Results available by reading ioport >60 msec after last port write. 92 93 0xff ==> no stereo detected, 0xfd ==> stereo detected. 94 95============================= ============================= 96Radio to Audio (path) Enable Description 97============================= ============================= 980 Disable path (silence) 991 Enable path (audio produced) 100============================= ============================= 101 102===== ===== ================== 103TuneA TuneB Description 104===== ===== ================== 1050 0 "zero" bit phase 1 1060 1 "zero" bit phase 2 1071 0 "one" bit phase 1 1081 1 "one" bit phase 2 109===== ===== ================== 110 111 11224-bit code, where bits = (freq*40) + 10486188. 113The Most Significant 11 bits must be 1010 xxxx 0x0 to be valid. 114The bits are shifted in LSb first. 115 116================== =========================== 117Tune Update Enable Description 118================== =========================== 1190 Tuner held constant 1201 Tuner updating in progress 121================== =========================== 122 123 124PROGRAMMING EXAMPLES 125-------------------- 126 127.. code-block:: none 128 129 Default: BASE <-- 0xc8 (current volume, no stereo detect, 130 radio enable, tuner adjust disable) 131 132 Card Off: BASE <-- 0x00 (audio mute, no stereo detect, 133 radio disable, tuner adjust disable) 134 135 Card On: BASE <-- 0x00 (see "Card Off", clears any unfinished business) 136 BASE <-- 0xc8 (see "Default") 137 138 Volume Down: BASE <-- 0x48 (volume down, no stereo detect, 139 radio enable, tuner adjust disable) 140 wait 10 msec 141 BASE <-- 0xc8 (see "Default") 142 143 Volume Up: BASE <-- 0x88 (volume up, no stereo detect, 144 radio enable, tuner adjust disable) 145 wait 10 msec 146 BASE <-- 0xc8 (see "Default") 147 148 Check Stereo: BASE <-- 0xd8 (current volume, stereo detect, 149 radio enable, tuner adjust disable) 150 wait 100 msec 151 x <-- BASE (read ioport) 152 BASE <-- 0xc8 (see "Default") 153 154 x=0xff ==> "not stereo", x=0xfd ==> "stereo detected" 155 156 Set Frequency: code = (freq*40) + 10486188 157 foreach of the 24 bits in code, 158 (from Least to Most Significant): 159 to write a "zero" bit, 160 BASE <-- 0x01 (audio mute, no stereo detect, radio 161 disable, "zero" bit phase 1, tuner adjust) 162 BASE <-- 0x03 (audio mute, no stereo detect, radio 163 disable, "zero" bit phase 2, tuner adjust) 164 to write a "one" bit, 165 BASE <-- 0x05 (audio mute, no stereo detect, radio 166 disable, "one" bit phase 1, tuner adjust) 167 BASE <-- 0x07 (audio mute, no stereo detect, radio 168 disable, "one" bit phase 2, tuner adjust)