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128k sample single channel generation

Posted: Fri Sep 15, 2017 7:57 pm
by eebbhh
Hi,
I am new to redpitaya.
I need to generate 128k sample arbitrary waveform periodically and continuously at 125 MHz rate in a single channel.
What could be the easiest solution in this case?
I have read many posts but still I am not sure which direction to take.
Thank you.

Re: 128k sample single channel generation

Posted: Wed Oct 11, 2017 11:19 am
by amike88
Hi,

for that you'd have to modify the PL (FPGA) code.
You would need to increase the size of the DAC/generator buffer by factor of 8. This should not be a too difficult task, as the code is mostly parametrised and only the change of few parameters should be necessary.
However all other modules, that use RAMB module in the FPGA, must be removed.
Zynq 10 has 2.1 Mb of memory available, and you would need 128k*16 = 2.05 Mb. You can see it just fits the FPGA.

Re: 128k sample single channel generation

Posted: Mon Oct 30, 2017 3:00 pm
by mishra.kanhaiya91
Is it possible to continuously stream a signal, meaning every cycle of transmission contains different data samples??

Re: 128k sample single channel generation

Posted: Thu Nov 02, 2017 11:52 am
by amike88
As is Red Pitaya does not support streaming at full speed.
The best you can do is to store 16k samples send them and write another 16k samples, however it takes a few clock samples to write a sample. To support full speed DMA would be needed.

Re: 128k sample single channel generation

Posted: Mon Oct 22, 2018 7:35 pm
by adamS
amike88 wrote:
Wed Oct 11, 2017 11:19 am
Hi,

for that you'd have to modify the PL (FPGA) code.
You would need to increase the size of the DAC/generator buffer by factor of 8. This should not be a too difficult task, as the code is mostly parametrised and only the change of few parameters should be necessary.
Hi,
I modify the "localparam RSZ = 15" in red_pitaya_asg.v and "input [ 15-1: 0] buf_addr_i" in red_pitaya_asg_ch.v ,
and then using the modified bitstream,
but the ASG output is wrong!
Do i wrong with any step?

Re: 128k sample single channel generation

Posted: Tue Oct 23, 2018 3:56 pm
by rsvoid
Hi,

I have done something similar with 16 Million data points, but using the KeheronSDK.

search on github for /rsarwar87/rp-adc-dac-dma

create a txt file with the relative ADC amplitude in floating point and place it in the same directory as the test.py.

for information on how to use the tools, look at the koheron SDK documentations