I’m trying to communicate via SPI between KRIA KV260 (master) and an ESP8266 (slave), through the PMOD port of the FPGA. I used PYNQ library provided by Xillinx, so that I can work in Jupyter Notebook and make C functions for communications and have them to be executed like a pith function (workflow recommended by their documentation). So I loaded the default Overlay (base.bit) to have access to the PMOD port and wrote the following functions in Jupyter Notebook (based on their wiki doc.: https://pynq.readthedocs.io/en/v3.0.0/pynq_libraries/pynqmb_reference.html#spi-devices):