I am new to SPI. I am little bit confused about its working. I know that it is synchronous. Let's say I want to read a value at address. So the process would be: First master will send address byte. For each bits in address byte sent by master, slave will also send bits. What are those bits sent by slave? After Address bit is sent, slave send the value at that requested location. For each bit in Value byte sent by slave, Master also send some bits to slave. What are those bits. SPI works on shift register. Please correct me if I am wrong.