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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/video4linux/radiotrack.txt |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
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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 | ---------------------------------------------------------------------------- | ||