RPI PICO SPI BOARD WORKING JUST FINE !!!
link here in tube >>> https://www.youtube.com/watch?v=vpB3R3BCyMs <<< Bulgarian language for now, english soon ;)
so, hello, as you can see the SPI expander is already working. the software was written on raspberry pico in the arduino development environment. the raspberry controls the expander with LED effects, everything is EXCELLENT !!! the additional board to the main development board of raspberry pico is an expander / expander / MCP23S17 SPI interface on 4 cables. there are 16 soldered LEDs on the board and nothing more. one power cord, one usb cable for communication to the arduino development environment and as you can see everything works perfectly. the effects are not great, I have done a few different ones with repetitions to see that the SPI communication works fast enough, maybe faster depends on what you will use the raspberry pico for.
the boards are in the set of raspberry pico for all specialists, students, programmers, lovers of electronics and programming and others. will be available for sale, the site has links for communication and orders. soon there will be an official price of the whole set as well as a full description for each board separately.
for now you can see the effects of the LEDs that I wrote in the source code of raspberry pico through the arduino development environment. It is extremely easy to work with, all the libraries from the old software of the PIC microchip processors that we have written for so many years and used have worked without any problem at all. easy adjustment of the definitions and control pins of the communication to the expander.