how to send data from SPI Slave Arduino to SPI Master Arduino

Projects Networking, Protocols, and Devices
3

In SPI, only master can initiate a transfer.

i have see many example in which master arduino receive data from slave like in Aruino library example Arduino master receive data from salve Barometric Pressure Sensor.

Also, there seems to be no support for slave mode SPI in standard Arduino library.

i use the Nick Gammon code as link is mention above ,to get this job