Add example configuring alternate SPI ports.

Author: nseidle

libraries/SPI/examples/Example1_SPI/Example1_SPI.ino

@@ -20,7 +20,7 @@ const char *msg = "Hello world!";
 void setup()
 {
 
-  Serial.begin(9600);
+  Serial.begin(115200);
   while (!Serial)
   {
   }; //Wait for user to open terminal window

libraries/SPI/examples/Example2_MoreSPIPorts/Example2_MoreSPIPorts.ino

@@ -0,0 +1,54 @@
+/* Author: Owen Lyke
+  Created: May 13 2019
+  License: MIT. See SparkFun Arduino Apollo3 Project for more information
+
+  This example demonstrates how to use Arduino SPI
+*/
+
+#include "SPI.h"
+
+#define CS_PIN 2
+
+#define SPI_SPEED 1000000
+#define SPI_ORDER MSBFIRST
+#define SPI_MODE SPI_MODE0
+
+SPISettings mySettings(SPI_SPEED, SPI_ORDER, SPI_MODE);
+
+const char *msg = "Hello world!";
+
+//SPIClass SPI(); //This is default and automatically defined on RedBoard/ATP/Nano. Uses pads 5/6/7 (SCK/MISO/MOSI).
+SPIClass SPI1(1); //Use IO Master 1 on pads 8/9/10
+// SPIClass mySPI(2); //Use IO Master 2 on pads 27/25/28
+// SPIClass anotherSPI(3); //Use IO Master 3 on pads 42/43/44
+// SPIClass SPI4(4); //Use IO Master 4 on pads 39/40/38
+// SPIClass SPI5(5); //Use IO Master 5 on pads 48/49/47
+
+void setup()
+{
+  Serial.begin(115200);
+  while (!Serial)
+  {
+  }; //Wait for user to open terminal window
+
+  Serial.println("SparkFun Arduino Apollo3 SPI Example");
+  Serial.printf("Compiled on %s, %s\n\n", __DATE__, __TIME__);
+
+  SPI1.begin();
+
+  pinMode(CS_PIN, OUTPUT);
+}
+
+void loop()
+{
+  digitalWrite(CS_PIN, LOW);
+  SPI1.beginTransaction(mySettings);
+  SPI1.transfer(0xAA);
+  SPI1.endTransaction();
+
+  SPI1.beginTransaction(mySettings);
+  SPI1.transferOut((void *)msg, strlen(msg));
+  SPI1.endTransaction();
+  digitalWrite(CS_PIN, HIGH);
+  delay(1000);
+}