RFSoC 4x2 How to generate square wave

[ljbedir]

<RFSoC 4x2 board, PYNQ version 3.0.1, connected over usb cable>

What I am asking is quite straight forward. Is it possible to generate square waves using one DAC only?

Thanks in advance.

[marioruiz]

Hi @ljbedir,

You can send the minimum value supported by the ADC for half the period and then the maximum value for the other half.

Mario

[ljbedir]

Hi @marioruiz,

Let me elaborate my question into a more clear wording: What would be the necessary python code?

Respectful regards,
Bedir

[marioruiz]

You can see how to use the DMA for data transfer here:

Tutorial: PYNQ DMA (Part 2: Using the DMA from PYNQ)

PYNQ DMA tutorial (Part 2: Using the DMA from PYNQ) This tutorial shows how to use the PYNQ DMA class to control an AXI DMA in a hardware design. This is the second part of a DMA tutorial. PYNQ DMA tutorial (Part 1: Hardware design) shows how to build the Vivado hardware design used in this notebook. All the source files for the tutorial are hosted on a GitHub repository and this post is a Markdown version of a Jupyter notebook. The original notebook can be found in the GitHub repository here …

You can do something like this numpy - Plot Square Wave in Python - Stack Overflow and then pass the square wave to the input_buffer.

[matthew]

Did you also check the DAC-ADC notebook from the base Overlay?
(RFSoC-PYNQ/boards/RFSoC4x2/base/notebooks/rfdc at master · Xilinx/RFSoC-PYNQ · GitHub)

[matthew]

Is it possible to use DMA, as the transmitter block does not have a DMA, only amplitude controllers without DMA?

[marioruiz]

Yes, you’ll need to add the DMA and make the necessary modifications to the overlay.

[matthew]

What are those necessary modifications? Changing the AXI_Lite connections to AXI4 connections?

[marioruiz]

Hi @matthew,

I would suggest the DMA tutorial to understand what are the changes.

https://discuss.pynq.io/t/tutorial-pynq-dma-part-1-hardware-design/3133/32

Mario