I need master and Slave codes.

It generic name is "bit banging

topic:ardunio

Your assignment in this lab session is to send a string from one Arduino board to another using SPI communication protocol. However, you are not allowed to use the SPI hardware. Instead, you must simulate the protocol via software. Use 4 pins on each board to create the four lines between the boards (MISO, MOSI, SS, and CLK). When the execution begins, the master board should send a short string to the slave. The message can be either terminated by a null character (O), or you can tell the slave that the transmission has ended by setting the SS line. Once the transmission is over, the slave should print the received message to the Serial Monitor