I'm looking to communicate between an ESP8266 and ATmega328p using SPI with the ATmega as master and ESP as slave. The reason I need the ESP to be slave is because the ATmega is already a SPI master for communicating with other slave devices.
I was originally planning to use NodeMCU on the ESP, however according to the documentation, the SPI library does not support SLAVE mode:
As an alternative to NodeMCU, I found that the ESP8266 Arduino core does include a SPISlave library:
https://github.com/esp8266/Arduino/tree ... s/SPISlave
I've read most of what I could find on this subject, and I did get the impression that it is something that is still being worked on, so there could be some recent developments that perhaps someone here knows about. Has anyone successfully implemented the ESP as a SPI Slave? If so, what method was used? Any suggestions?