Cleanup SPI_Multiple_Buses (espressif#3527)

* Utilize prepoc symbols for SPI pins * Adjusts for GPIO pins when ALTERNATE_PINS is set

Author: muman613

libraries/SPI/examples/SPI_Multiple_Buses/SPI_Multiple_Buses.ino

@@ -15,6 +15,30 @@
  */
 #include <SPI.h>
 
+// Define ALTERNATE_PINS to use non-standard GPIO pins for SPI bus
+
+#ifdef ALTERNATE_PINS
+ #define VSPI_MISO 2
+ #define VSPI_MOSI 4
+ #define VSPI_SCLK 0
+ #define VSPI_SS 33
+
+ #define HSPI_MISO 26
+ #define HSPI_MOSI 27
+ #define HSPI_SCLK 25
+ #define HSPI_SS 32
+#else
+ #define VSPI_MISO MISO
+ #define VSPI_MOSI MOSI
+ #define VSPI_SCLK SCK
+ #define VSPI_SS SS
+
+ #define HSPI_MISO 12
+ #define HSPI_MOSI 13
+ #define HSPI_SCLK 14
+ #define HSPI_SS 15
+#endif
+
 static const int spiClk = 1000000; // 1 MHz
 
 //uninitalised pointers to SPI objects
@@ -28,22 +52,28 @@ void setup() {
 
  //clock miso mosi ss
 
+#ifndef ALTERNATE_PINS
  //initialise vspi with default pins
  //SCLK = 18, MISO = 19, MOSI = 23, SS = 5
  vspi->begin();
+#else
  //alternatively route through GPIO pins of your choice
- //hspi->begin(0, 2, 4, 33); //SCLK, MISO, MOSI, SS
- 
+ vspi->begin(VSPI_SCLK, VSPI_MISO, VSPI_MOSI, VSPI_SS); //SCLK, MISO, MOSI, SS
+#endif
+
+#ifndef ALTERNATE_PINS
  //initialise hspi with default pins
  //SCLK = 14, MISO = 12, MOSI = 13, SS = 15
- hspi->begin(); 
+ hspi->begin();
+#else
  //alternatively route through GPIO pins
- //hspi->begin(25, 26, 27, 32); //SCLK, MISO, MOSI, SS
+ hspi->begin(HSPI_SCLK, HSPI_MISO, HSPI_MOSI, HSPI_SS); //SCLK, MISO, MOSI, SS
+#endif
 
  //set up slave select pins as outputs as the Arduino API
  //doesn't handle automatically pulling SS low
- pinMode(5, OUTPUT); //VSPI SS
- pinMode(15, OUTPUT); //HSPI SS
+ pinMode(VSPI_SS, OUTPUT); //VSPI SS
+ pinMode(HSPI_SS, OUTPUT); //HSPI SS
 
 }
 
@@ -60,18 +90,18 @@ void vspiCommand() {
 
  //use it as you would the regular arduino SPI API
  vspi->beginTransaction(SPISettings(spiClk, MSBFIRST, SPI_MODE0));
- digitalWrite(5, LOW); //pull SS slow to prep other end for transfer
+ digitalWrite(VSPI_SS, LOW); //pull SS slow to prep other end for transfer
  vspi->transfer(data); 
- digitalWrite(5, HIGH); //pull ss high to signify end of data transfer
+ digitalWrite(VSPI_SS, HIGH); //pull ss high to signify end of data transfer
  vspi->endTransaction();
 }
 
 void hspiCommand() {
  byte stuff = 0b11001100;
 
  hspi->beginTransaction(SPISettings(spiClk, MSBFIRST, SPI_MODE0));
- digitalWrite(15, LOW);
+ digitalWrite(HSPI_SS, LOW);
  hspi->transfer(stuff);
- digitalWrite(15, HIGH);
+ digitalWrite(HSPI_SS, HIGH);
  hspi->endTransaction();
 }