* Inform slave of a master button press. * SPI pin numbers: * SCK 13 // Serial Clock. * MISO 12 // Master In Slave Out. * MOSI 11 // Master Out Slave In. * SS 10 ...

I have code that has been working for a long time. It uses hardware SPI to communicate with a couple devices. After updating from Arduino IDE 2.0.4 to Arduino IDE 2.1.0, hardware SPI no longer works.