seems like I somehow managed to send this twice.
On 05.11.22 20:23, Marcus Müller wrote:
Hi Roland,
On 05.11.22 14:00, Roland Schwarz wrote:
Unfortunately it seem I put the cart before the horse by having submitted a bug request
about something I expected to work but now find needs more thought.
Ha! "I, as a user, am in a reasonable expectation that something should work, now I
figure it doesn't" might also indicate that some things might be in need of better
documentation!
I hope this mailing list is the right place for discussion.
So far it's been a fantastic place :)
HackRF One is a device designed for half duplex operations, this is why I believe it is
safe to assume it will be able to do burst transmissions on a hardware level.
There's a TX amp/RX amp/bypass switch (U12/U14), controlled by the logic, which could
indeed be used for rapidly switching off TX.
Unfortunately the gr-soapy driver, which implements burst transmission which will work
with UHD (at least I have been told so), don't work with the SoapyHackRF driver to do
burst mode.
I guess what that means is that when the Soapy sink is in tagged bursts mode (you set a
length tag), it will set the the SOAPY_SDR_END_BURST flag at the right point after a
length tag, before sending the samples and flags off to the underlying device driver.
UHD knows how to deal with that; there's a mechanism to transport that "OK, and after
that last sample of this sample packet, you stop transmitting" info from PC to do device.
So far I have not found a description or even mentioning of burst mode in the soapy
driver model documents. Since I was told the gr-soapy driver will work with UHD I was
looking for a SoapyUHD or the like, but there is none.
Dunno where you look, but at the place where JBlum keeps his SoapySDR, he also keeps his
SoapyUHD:
https://github.com/pothosware/SoapyUHD
I found
Soapy BladeRF Sink
Soapy Custom Sink
Soapy HackRF Sink
Soapy LimeSDR Sink
Soapy PLUTO Sink
however not Soapy UHD Sink. What am I misunderstaning here?
These sinks are just "convenience sinks". SoapySDR is a plugin architecture: there's
just actually one block, the Soapy sink, and it doesn't know which hardware you have, or
how to talk to that – but you can install plugins for SoapySDR that actually know
hardware, and then you can stream to that hardware.
These inidividual sinks just "pre-fill" all the configuration so that this type of
device is used, and that the device-specific settings are done.
Has anyone already considered burst mode or has experience with any of BladeRF, LimeSDR
or PLUTO drivers?
No experience on my side with TX bursting.
But, source code tells me the SoapySDR driver for HackRF does support handing down the
"end of stream" information to the device:
https://github.com/pothosware/SoapyHackRF/blob/4e40fa19fa3b64f335d48ce112859acbaecee6c4/HackRF_Streaming.cpp#L386
So, should work the same as when using a USRP instead of a HackRF.
Best regards,
Marcus
