I may well have missed or not understood what was presented in the various tutorials and threads but, I cannot figure out how to use the Yun as an SPI “slave”. Though some threads seem unresolved, I don’t see that the Yun’s use as an SPI “slave” is actually possible or not possible.
As background, this is for a home monitor and security project which has a Mega doing everything and the Mega was to be my “master” since it will know of any alerts that need to be made and have the status information to be posted. The Yun was to be my “slave”, receiving info from the Mega and, subsequently using the Yun’s Ethernet connection to send alerts via SMS and provide web posting of the status information. The only data transfer needed is between the Yun and the Mega - there is no other SPI or I2C connectivity in this project.
The SS signal on the Yun is my specific problem and if someone could direct me to handling its connectivity and/or code alternative, it would be most appreciated. Thanks for your interest.