Just realized that there *is* a C++ API:
usrp_block->get_device()->get_rx_dboard_iface()->read_aux_adc();
replace _rx_ with _tx_ for the LFTX, and read_aux_adc with write_aux_dac for
the DAC.
Best regards,
Marcus
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On 05.03.22 13:31, Marcus Müller wrote:
Hi Fabien,
no need to modify the FPGA. The functionality is there – it's just not exposed to the
user. Also, note that interacting with the auxiliary ADC and DAC is going to be
asynchronous to the sample flow – there might be millions of samples from the main ADC
that have flown by before an AUX_DAC setting takes effect!
You also don't really need to modify UHD – you *can* use the UHD property tree (through
uspr_block->get_device()->get_tree()->access() ), it's just not a proper, stable,
well-tested, failure-checking API.
Best regards,
Marcus
On 04.03.22 15:01, Fabien PELLET wrote:
Yes, sorry indeed I was talking about AUX_DAC and AUX_ADC that are replicated from the
motherboard.
I already use IO which works very well. So there is no way to send samples (or receive)
at a specific sample rate using that AUX_DAC or ADC. It is just some "analog IOs" for
reading some external sensors for example if I understand well what you wrote.
What are the specifications of that AUX ?
Using a specifique FPGA firmware and custom UHD library, would it be possible to
transform them as GR source or sink ?
Thanks,
Best regards,
Fabien, F4CTZ.
Le 04/03/2022 à 14:35, Marcus Müller a écrit :
Sorry, hit "send" accidentally:
Dear Fabien,
there's no ADC on these daughterboards. Just an EEPROM for identification, opamps for
amplification and signal conditioning, and on the LFTX a switch-mode power supply.
You're right, they do exppose the AUX DACs and ADC lines from the motherboad.
However, these are without further ado not accessible from UHD, and thus also not from
GNU Radio. Some daughterboard drivers use them.
I'm not sure UHD exposes them in all version, but `uhd_usrp_probe --tree` might show
properties called "AUX_DAC_A" (or _B, or AUX_ADC_.., you get the idea). You can use
get_device() on your USRP blocks and access theses properties from your GNU Radio
program (from C++), but it's not really an API – more an exposing of intestines...
Best regards,
Marcus
On 04.03.22 14:30, Marcus Müller wrote:
Dear Fabien,
there's no ADC on these daughterboards. Just an EEPROM for identification, opamps for
amplification and signal conditioning, and on the LFTX a switch-mode power supply.
Best regards,
Marcus
On 04.03.22 10:30, Fabien PELLET wrote:
Hello,
As there are IOs available on LFTX and LFRX, there are also ADC and DAC
available.
Is there a way to use them as SOURCE and SINK in gnuradio for low speed
conversion ?
Thanks,
Best regards,
Fabien, F4CTZ.
