Uno to Micro via SPI

I'm just starting to get my feet wet with SPI. Can anyone point me to some basic examples for connecting 2 Arduino via SPI? Thanks

Nick Gammon tells you how to do that: http://www.gammon.com.au/forum/?id=10892.

But take care to use the Micro as the master because it's SS pin is used for the RX LED and is not available on the pinout. The UNO as the slave is no problem though.

Just what I needed, thanks. Could I use the Micro ICSP SS pin to use it as a slave?

Hi Jude332

It´s correct!! you HAVE TO use the SSpin for the Slave micro

"The system consists of two shift Registers, and a Master clock generator. The SPI Master initiates the communication cycle when pulling low the Slave Select SS pin of the desired Slave. Master and Slave prepare the data to be sent in their respective shift Registers, and the Master generates the required clock pulses on the SCK line to interchange data.Data is always shifted from Master to Slave on the Master Out – Slave In, MOSI, line, and from Slave to Master on the Master In – Slave Out, MISO, line. After each data packet, the Master will synchronize the Slave by pulling high the Slave Select, SS,line "

Page 167, ATmega328P Manual, ISP section [http://www.atmel.com/Images/doc8161.pdf]

regards!!

C.JPG

Jude332: Just what I needed, thanks. Could I use the Micro ICSP SS pin to use it as a slave?

The ICSP don't have an SS pin, you cannot access the Micro's SS pin without modifying the board. Use another board if the smaller one must be the slave.