mirror of
https://github.com/torvalds/linux
synced 2024-11-05 18:23:50 +00:00
147 lines
5.7 KiB
Text
147 lines
5.7 KiB
Text
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)
|
|
|
|
----------------------------------------------------------------------------
|