The original device now gets incorrect data. For the last several weeks, [Paul] has been working on a new Arduino SPI library, to solve these types of conflicts. In the above scenario ...

Each of the 14 digital pins on the Arduino Uno can be used as an input or output ... Provide 8-bit PWM output with the analogWrite() function. SPI: 10 (SS), 11 (MOSI), 12 (MISO), 13 (SCK). These pins ...