Re: N210 DAC and ADC usage

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.
>>>>
>>>>
>>
>