Hi Vladica, Although the N321 has 1GB RAM, it is not used by default in a receive channel. The RFNoC block rfnoc_block_axi_ram_fifo is the block that uses this external RAM so you would need this block in your FPGA binary image in order to use it. I don't think that this block is included in the default image which means you would need to build a new image with this block included. Further, I have never tried this block in a receive channel so while it seems it would solve your issue, I am not certain.
Using the 1Gbe connection, your max data rate (aggregate across all channels) is about 25 MS/s for sustained streaming. You could use a faster rate for a very short burst so long as your FPGA buffer is big enough to store all samples. But, without the axi_ram_fifo block, the size of such buffers are quite limited as you have seen. If you have capability to build a new image, you may be able increase the size of the relevant SEP buffers to handle your 100k sample requirement. Regarding triggering, I don't think this capability exists but you could add a custom block to do this. See here <https://kb.ettus.com/Getting_Started_with_RFNoC_in_UHD_4.0> for the list of blocks that Ettus provides. In particular, look at the logpwr block which could be useful in detecting a threshold. But, you would then need to implement the logic to discard samples prior to the trigger and then forward the samples after the trigger. Rob On Thu, Apr 8, 2021 at 8:50 AM Chang, Kaixin <[email protected]> wrote: > Hi Vladica, I think the overflow means that the host pc cannot process the > data flow fast enough or you might need to set the parameter timeout of > recv(buff_ptrs, num_rx_samps, md, timeout) > a bit longer? > > > Sincerely > > > Kasim > ------------------------------ > *From:* Vladica Sark <[email protected]> > *Sent:* 08 April 2021 14:46:08 > *To:* [email protected] > *Subject:* [USRP-users] Timed samples overflow > > Hello folks, > > > I would like to receive a relatively short burst of timed samples (eg. > 100k) on a N321 and get them over 1 Gbps Ethernet on the PC. The problem > is that I get an overflow condition every time I try to receive more > than 10k samples. According to the data for the N321, it has 1 or 2 GB > memory, enough for 100k samples, so this number of samples can be stored > in the RAM and than sent to the PC. Unfortunately, this is not > happening. Is there a workaround for this issue? > > I use rx_timed_samples for this. With 10 Gbps Ethernet everything is OK. > > > Also, I want to ask if it is possible to trigger the sample acquisition > on a given input signal level, i.e. threshold? > > > Best regards, > > Vladica > > > > _______________________________________________ > USRP-users mailing list -- [email protected] > To unsubscribe send an email to [email protected] > _______________________________________________ > USRP-users mailing list -- [email protected] > To unsubscribe send an email to [email protected] >
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