forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
167 lines
5.1 KiB
167 lines
5.1 KiB
.. SPDX-License-Identifier: GPL-2.0 |
|
|
|
.. include:: <isonum.txt> |
|
|
|
The Silicon Labs Si470x FM Radio Receivers driver |
|
================================================= |
|
|
|
Copyright |copy| 2009 Tobias Lorenz <[email protected]> |
|
|
|
|
|
Information from Silicon Labs |
|
----------------------------- |
|
|
|
Silicon Laboratories is the manufacturer of the radio ICs, that nowadays are the |
|
most often used radio receivers in cell phones. Usually they are connected with |
|
I2C. But SiLabs also provides a reference design, which integrates this IC, |
|
together with a small microcontroller C8051F321, to form a USB radio. |
|
Part of this reference design is also a radio application in binary and source |
|
code. The software also contains an automatic firmware upgrade to the most |
|
current version. Information on these can be downloaded here: |
|
http://www.silabs.com/usbradio |
|
|
|
|
|
Supported ICs |
|
------------- |
|
|
|
The following ICs have a very similar register set, so that they are or will be |
|
supported somewhen by the driver: |
|
|
|
- Si4700: FM radio receiver |
|
- Si4701: FM radio receiver, RDS Support |
|
- Si4702: FM radio receiver |
|
- Si4703: FM radio receiver, RDS Support |
|
- Si4704: FM radio receiver, no external antenna required |
|
- Si4705: FM radio receiver, no external antenna required, RDS support, Dig I/O |
|
- Si4706: Enhanced FM RDS/TMC radio receiver, no external antenna required, RDS |
|
Support |
|
- Si4707: Dedicated weather band radio receiver with SAME decoder, RDS Support |
|
- Si4708: Smallest FM receivers |
|
- Si4709: Smallest FM receivers, RDS Support |
|
|
|
More information on these can be downloaded here: |
|
http://www.silabs.com/products/mcu/Pages/USBFMRadioRD.aspx |
|
|
|
|
|
Supported USB devices |
|
--------------------- |
|
|
|
Currently the following USB radios (vendor:product) with the Silicon Labs si470x |
|
chips are known to work: |
|
|
|
- 10c4:818a: Silicon Labs USB FM Radio Reference Design |
|
- 06e1:a155: ADS/Tech FM Radio Receiver (formerly Instant FM Music) (RDX-155-EF) |
|
- 1b80:d700: KWorld USB FM Radio SnapMusic Mobile 700 (FM700) |
|
- 10c5:819a: Sanei Electric, Inc. FM USB Radio (sold as DealExtreme.com PCear) |
|
|
|
|
|
Software |
|
-------- |
|
|
|
Testing is usually done with most application under Debian/testing: |
|
|
|
- fmtools - Utility for managing FM tuner cards |
|
- gnomeradio - FM-radio tuner for the GNOME desktop |
|
- gradio - GTK FM radio tuner |
|
- kradio - Comfortable Radio Application for KDE |
|
- radio - ncurses-based radio application |
|
- mplayer - The Ultimate Movie Player For Linux |
|
- v4l2-ctl - Collection of command line video4linux utilities |
|
|
|
For example, you can use: |
|
|
|
.. code-block:: none |
|
|
|
v4l2-ctl -d /dev/radio0 --set-ctrl=volume=10,mute=0 --set-freq=95.21 --all |
|
|
|
There is also a library libv4l, which can be used. It's going to have a function |
|
for frequency seeking, either by using hardware functionality as in radio-si470x |
|
or by implementing a function as we currently have in every of the mentioned |
|
programs. Somewhen the radio programs should make use of libv4l. |
|
|
|
For processing RDS information, there is a project ongoing at: |
|
http://rdsd.berlios.de/ |
|
|
|
There is currently no project for making TMC sentences human readable. |
|
|
|
|
|
Audio Listing |
|
------------- |
|
|
|
USB Audio is provided by the ALSA snd_usb_audio module. It is recommended to |
|
also select SND_USB_AUDIO, as this is required to get sound from the radio. For |
|
listing you have to redirect the sound, for example using one of the following |
|
commands. Please adjust the audio devices to your needs (/dev/dsp* and hw:x,x). |
|
|
|
If you just want to test audio (very poor quality): |
|
|
|
.. code-block:: none |
|
|
|
cat /dev/dsp1 > /dev/dsp |
|
|
|
If you use sox + OSS try: |
|
|
|
.. code-block:: none |
|
|
|
sox -2 --endian little -r 96000 -t oss /dev/dsp1 -t oss /dev/dsp |
|
|
|
or using sox + alsa: |
|
|
|
.. code-block:: none |
|
|
|
sox --endian little -c 2 -S -r 96000 -t alsa hw:1 -t alsa -r 96000 hw:0 |
|
|
|
If you use arts try: |
|
|
|
.. code-block:: none |
|
|
|
arecord -D hw:1,0 -r96000 -c2 -f S16_LE | artsdsp aplay -B - |
|
|
|
If you use mplayer try: |
|
|
|
.. code-block:: none |
|
|
|
mplayer -radio adevice=hw=1.0:arate=96000 \ |
|
-rawaudio rate=96000 \ |
|
radio://<frequency>/capture |
|
|
|
Module Parameters |
|
----------------- |
|
|
|
After loading the module, you still have access to some of them in the sysfs |
|
mount under /sys/module/radio_si470x/parameters. The contents of read-only files |
|
(0444) are not updated, even if space, band and de are changed using private |
|
video controls. The others are runtime changeable. |
|
|
|
|
|
Errors |
|
------ |
|
|
|
Increase tune_timeout, if you often get -EIO errors. |
|
|
|
When timed out or band limit is reached, hw_freq_seek returns -EAGAIN. |
|
|
|
If you get any errors from snd_usb_audio, please report them to the ALSA people. |
|
|
|
|
|
Open Issues |
|
----------- |
|
|
|
V4L minor device allocation and parameter setting is not perfect. A solution is |
|
currently under discussion. |
|
|
|
There is an USB interface for downloading/uploading new firmware images. Support |
|
for it can be implemented using the request_firmware interface. |
|
|
|
There is a RDS interrupt mode. The driver is already using the same interface |
|
for polling RDS information, but is currently not using the interrupt mode. |
|
|
|
There is a LED interface, which can be used to override the LED control |
|
programmed in the firmware. This can be made available using the LED support |
|
functions in the kernel. |
|
|
|
|
|
Other useful information and links |
|
---------------------------------- |
|
|
|
http://www.silabs.com/usbradio
|
|
|