I have been hacking into one of those $20 DVB-T TV Tuner Dongles. To get it
to tune to the Freq I want I use the usual method with the ExtIO Drivers.
The real problem with this thing, as far as making good use of the valuable
E4000, is the RTL2832, even though controlling the Tuner through the USB
requires the RTL2832. This clumsy Analog to Digital Converter / USB
interface Chip, does not have the Audio dynamic range needed for my
purposes. The infuriating predilection it has to crash every time you want
to shift frequency is another disadvantage.
Since the Owners of the E4000 have gone into Bankruptcy, I am taking the
initiative to hack the Tuner.
First, I attached a high gain audio amplifier's input directly to the
Tuner's output then to a 96K Sample per Second, 24 Bit Audio card to observe
a high quality spectral image from the tuner.
Next is to hack into and record the I2C sent to the Tuner, so it may be
controlled independent of that infuriating RTL2832. If anyone has done this,
please share your code and understanding.
Thanks
Jay Salsburg
Sent via the HTC V..b.livid™, anbURL: http://maps.google.com/maps?q=40.031769,-105.2;Kn)na?bks3213, 3128 Bell Dr, Boulder, CO 80301, USA AT&T 4G -3$/-)44+$LTE( (::,2mk:
----- Reply message -----
From: "Christian Gagneraud" <chris(a)techworks.ie>
To: "Dimitri Stolnikov" <horiz0n(a)gmx.net>
Cc: <discuss-gnuradio(a)gnu.org>, <osmocom-sdr(a)lists.osmocom.org>
Subject: [Discuss-gnuradio] FCD/Alsa bug (Re: Bug hunting)
Date: Wed, Aug 8, 2012 9:02 am
Cross posting to discuss-gnuradio.
The bug in question is that if you instanciate an alsa source on a busy device (opened by another app), then the program crashed.
On 08/08/12 00:23, Dimitri Stolnikov wrote:
> Hi Christian,
[...]
>
> The other problem (segfault on trow in ctor) still has to be addressed.
Yes, I started to investigate, and it seems to me that this is not a gr-osmosdr bug, but it's a gnuradio one, caused by gr-fcd.
This simple test program have the same problem, yet it only uses gr-fcd.
#include <iostream>
#include <fcd_source_c.h>
int main(int argc, char **argv)
{
fcd_source_c_sptr fsrc;
try {
fsrc = fcd_make_source_c("hw:2"); // KO, from gr-fcd
}
catch (std::runtime_error &e) {
std::cerr << "Error!\n";
}
exit(0);
}
g++ test.cc -o test -I/usr/local/include/gnuradio -lgnuradio-fcd
Here is the log:
audio_alsa_source[hw:2]: Device or resource busy
Error!
*** glibc detected *** /home/cgagneraud/sdr/gr-osmosdr/test: free(): invalid pointer: 0x08052e3c ***
[...]
And here is a cleaned up backtrace:
operator delete
gruel::msg_accepter::~msg_accepter
checked_delete<gr_hier_block2>
boost::detail::sp_counted_impl_p<gr_hier_block2>::dispose
[...]
const, boost::shared_ptr<gr_basic_block> > > >::~map
__cxa_finalize
__do_global_dtors_aux
[...]
main
The problem is related to gnuradio-core/src/lib/runtime/gr_sptr_magic.{h,cc} and the static std::map in there.
gr_hier_block2 ctor insert "this" in this map, but then in fcd_source ctor, audio_alsa_source ctor throws an exception, so "this" (gr_hier_block2/fcd_source) is not a valid pointer anymore.
When the program exits, the map get cleanup up and free is called on this pointer.
It's not possible to cleanup the map in fcd_source, because the dtor is not called when exception occurs in the ctor (which, btw, leads to some memory leaks in alsa_source: namely d_hw_params and d_sw_params).
It's a bad idea to call fetch_initial_sptr(this) before throwing in the ctor, because it seems the object get deleted.
First off, this is my first post to the group and I want to thank everyone
who has worked to get this kit as far as it is; I was deathly worried that
I might be stuck with unusable hardware, and it is still unusuable, but
there seems to be light at the end of the SDR tunnel and I'm hoping this is
the right forum for asking newbie questions :)
Here's where I am so far: I have the Hama Nano DVB-T+DAB+FM with the
Elonics E4000 tuner and my goal is really very modest (I hope) in that I
only want to tune in one ordinary analog FM station, the FM transmitter in
the next room that supplies our house with music from our MP3 collection.
Rather than pay $40 at walmart for a radio for my lab, I thought I'd spend
$20 on the USB device and have some fun in the process.
And it's been fun: I found the recipe for the rtl_fm using the alsa aplay,
and I assume the examples were concerned with some other sort of radio
(shortwave?) because the recommended 48k sampling sounded like a taxi
radio! Not really Easy Listening sort of audio.
with some experimenting I found a formula that is still heavily distorted,
but recognizable as music:
rtl_fm -f 96.3e6 -s 192000 -l 5 -| aplay -t raw -f s16_le -r 192k -c 1
the trouble was that it wouldn't play continuously on my 3300-bogomips
netbook, so I moved the code over to my 64-bit dual-core laptop and that's
where a strange thing happened: when run as a regular user, the code aborts
giving strange (unicode?) gibberish as the device name, but when run as
root, the name is correctly reported although the program aborts.
~/Work/dev$ rtl_fm -f 96.3k -s 192000 - | aplay -t raw -r 192k -f s16_le
Found 1 device(s):
0: , mX��, SN: ��z�
Using device 0: Generic RTL2832U (e.g. hama nano)
usb_open error -3
Failed to open rtlsdr device #0.
~/Work/dev$ sudo rtl_fm -f 96.3k -s 192000 - | aplay -t raw -r 192k -f
s16_le
Found 1 device(s):
0: Generic, RTL2832U, SN: 77771111153705700
Using device 0: Generic RTL2832U (e.g. hama nano)
usb_claim_interface error -6
Failed to open rtlsdr device #0.
on the 32-bit platform, the *Using device* line is followed by
Found Elonics E4000 tuner
Oversampling input by: 6x
Oversampling output by: 1x
is there perhaps some simple config setting that I've overlooked in the
64-bit box? Both are running Ubuntu 12.04
here are the kernel messages on loading the device on 64bit
Aug 9 13:47:58 strata kernel: [200306.632008] usb 3-1: new high-speed USB
device number 3 using xhci_hcd
Aug 9 13:47:58 strata kernel: [200306.663830] usb 3-1: ep 0x81 - rounding
interval to 32768 microframes, ep desc says 0 microframes
Aug 9 13:47:58 strata kernel: [200306.669822] dvb-usb: found a 'RTL2832U
DVB-T USB DEVICE' in warm state.
Aug 9 13:47:58 strata kernel: [200306.669840] dvb-usb: will pass the
complete MPEG2 transport stream to the software demuxer.
Aug 9 13:47:58 strata kernel: [200306.671500] DVB: registering new adapter
(RTL2832U DVB-T USB DEVICE)
Aug 9 13:47:58 strata kernel: [200306.689815] RTL2832U
usb_init_bulk_setting : USB2.0 HIGH SPEED (480Mb/s)
Aug 9 13:47:58 strata mtp-probe: checking bus 3, device 3:
"/sys/devices/pci0000:00/0000:00:1c.3/0000:09:00.0/usb3/3-1"
Aug 9 13:47:59 strata kernel: [200306.972506] RTL2832U check_tuner_type :
E4000 tuner on board...
Aug 9 13:47:59 strata mtp-probe: bus: 3, device: 3 was not an MTP device
Aug 9 13:47:59 strata kernel: [200307.552737] DVB: registering adapter 0
frontend 0 (Realtek DVB-T RTL2832)...
Aug 9 13:47:59 strata kernel: [200307.553116] input: IR-receiver inside an
USB DVB receiver as
/devices/pci0000:00/0000:00:1c.3/0000:09:00.0/usb3/3-1/input/input15
Aug 9 13:47:59 strata kernel: [200307.553243] dvb-usb: schedule remote
query interval to 287 msecs.
Aug 9 13:47:59 strata kernel: [200307.553251] dvb-usb: RTL2832U DVB-T USB
DEVICE successfully initialized and connected.
I notice that it DOESN'T say "*will pass the complete MPEG2 transport
stream to the software demuxer"* as it does on the 32bit side.
Also, what is the syntax for the -g switch? I have tried integers,
decimals and the string -3dB and in all cases I get the message *Warning:
Failed to set tuner gain* -- could the gain control simply be unsupported
by my device?
Lastly, I'd like to ask the hard question: are my goals here feasible? Is
this an appropriate device for listening to FM broadcasts at the computer
or is this more a hobbyist's SDR playground and, like a dancing bear, the
bear doesn't dance amazingling, it is only amazing that the bear dances at
all ;)
--
*Have Blog, Will Travel: blog.teledyn.com*
*A Serviceable Substitute: post.teledyn.com*
Hi,
Is there any bug tracker for the gr-osmosdr somewhere?
It would be nice if the "audio_alsa_source[hw:X]: Device or resource
busy" could be fixed.
The problem with that bug is you can't even interogate the device driver
for supported gain, etc... If the device is used by another application.
For example, I have permanently 2 devices plugged in, I use an FCD to
send AIS data to aishub.com, and a RTL to experiment with.
The problem with this bug is that if you use python you can't even catch
the exception, it simply crash the script. I think that the behaviour is
different when using C++.
Another "bug" I discovered is that if you just do a device scan to print
available device and exit the python script, it will generate plenty of
error messages like "libusb:warning [cancel_bulk_transfer] unrecognised
discard errno 9", the workaround is to simply wait a bit before exiting.
It seems that some USB packets are still pending after calling
osmosdr.source_c().
Chris
--
Christian Gagneraud,
Embedded systems engineer.
Techworks Marine
1 Harbour road
Dun Laoghaire
Co. Dublin
Ireland
Tel: + 353 (0) 1 236 5990
Web: http://www.techworks.ie/
From: Christian Gagneraud <chris(a)techworks.ie>
gr-osmosdr uses the driver in a multi-thread context, as a side effect the
cancel_async() can be called before read_async(), in such a case the cancel is
"forgotten". This patch fixed that by being a bit more relaxed with
state machine transitions.
This patch doesn't fix any race conditions, it just make an anoying one less
likely to happen.
This patch goes along this one [1]
[1] http://lists.osmocom.org/pipermail/osmocom-sdr/2012-August/000201.html
Signed-off-by: Christian Gagneraud <chris(a)techworks.ie>
---
src/librtlsdr.c | 10 +++++++---
1 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/src/librtlsdr.c b/src/librtlsdr.c
index 4e54d8e..d83010d 100644
--- a/src/librtlsdr.c
+++ b/src/librtlsdr.c
@@ -1256,6 +1256,12 @@ int rtlsdr_read_async(rtlsdr_dev_t *dev, rtlsdr_read_async_cb_t cb, void *ctx,
if (!dev)
return -1;
+ /* It can happen if cancel_async is called before read_async */
+ if (dev->async_status != RTLSDR_INACTIVE)
+ return -1;
+
+ dev->async_status = RTLSDR_RUNNING;
+
dev->cb = cb;
dev->cb_ctx = ctx;
@@ -1284,8 +1290,6 @@ int rtlsdr_read_async(rtlsdr_dev_t *dev, rtlsdr_read_async_cb_t cb, void *ctx,
libusb_submit_transfer(dev->xfer[i]);
}
- dev->async_status = RTLSDR_RUNNING;
-
while (RTLSDR_INACTIVE != dev->async_status) {
r = libusb_handle_events_timeout(dev->ctx, &tv);
if (r < 0) {
@@ -1326,7 +1330,7 @@ int rtlsdr_cancel_async(rtlsdr_dev_t *dev)
if (!dev)
return -1;
- if (RTLSDR_RUNNING == dev->async_status) {
+ if (RTLSDR_CANCELING != dev->async_status) {
dev->async_status = RTLSDR_CANCELING;
return 0;
}
--
1.7.7
Hi there,
I saw a message in the July archive (I wasn't subscribed yet at that
date) about updating gr-ais with osmosdr support.
I was working on the same thing recently, so i decided to publish my
fixes on top of Antoine's one.
The result can be found here:
https://github.com/chgans/gr-ais
I got it working with both an FCD and an RTL:
ais_rx.py --rate 96e3 --gain 30 --error -17 -d -D fcd=0
ais_rx.py --rate 1024e3 --gain 30 --error -110 -d -D rtl=0
Strangely passing freq_err=XX parameter to the source (using -D),
doesn't work, the use of --error is thus needed (which will do a
set_freq_corr()).
Antoine, if you want sample file, just let me know.
Nick, are you willing to integrate these changing back in gr-ais, Apart
from the added automatic decimation filter, the changes are not
intrusive at all.
The default settings for UHD are 256Khz sampling with decimation filter
4, with this change, the decimation is one when using FCD (96KHz fixed
frequency) and 16 for RTL when used at 1.024MHz (this was the minimum
working frequency for me).
Or maybe would you prefer to allow the user to set it manually, and use
this technique as a fall back only.
Please let me know what you guys think.
Thx,
Chris
--
Christian Gagneraud,
Embedded systems engineer.
Techworks Marine
1 Harbour road
Dun Laoghaire
Co. Dublin
Ireland
Tel: + 353 (0) 1 236 5990
Web: http://www.techworks.ie/
Hi,
I started do add documentation to the wiki page of gr-osmosdr [1].
For now i've just added documentation about the "constructor"
parameters. Any feedback welcome.
[1] http://sdr.osmocom.org/trac/wiki/GrOsmoSDR
PS: Could anyone tell me what the mcr is? (used for osmosdr source)
--
Christian Gagneraud,
Embedded systems engineer.
Techworks Marine
1 Harbour road
Dun Laoghaire
Co. Dublin
Ireland
Tel: + 353 (0) 1 236 5990
Web: http://www.techworks.ie/
Hi there,
In a python script, I would like to iterate over things like
get_gain_names, get_gain_ranges, ...
The problem is that these functions return a std::vector<std::string> *.
The error i get is: TypeError: 'SwigPyObject' object is not iterable
It would be very nice to be able to do something like:
for src.get_sample_rates():
# do something
for name in get_gain_names():
# do smth
I found this: http://reference-man.com/files/generators.i
But i haven't been able to use it so far. :(
Any help or comments appreciated.
Chris
--
Christian Gagneraud,
Embedded systems engineer.
Techworks Marine
1 Harbour road
Dun Laoghaire
Co. Dublin
Ireland
Tel: + 353 (0) 1 236 5990
Web: http://www.techworks.ie/
