Get external SPI SD reader working on M5StickC-Plus

esp32_marauder/SDInterface.cpp

@@ -1,6 +1,7 @@
 #include "SDInterface.h"
 #include "lang_var.h"
 
+
 bool SDInterface::initSD() {
   #ifdef HAS_SD
     String display_string = "";
@@ -20,8 +21,23 @@ bool SDInterface::initSD() {
     pinMode(SD_CS, OUTPUT);
 
     delay(10);
-  
-    if (!SD.begin(SD_CS)) {
+    #if defined(MARAUDER_M5STICKC)
+      /* Set up SPI SD Card using external pin header
+      StickCPlus Header - SPI SD Card Reader
+                  3v3   -   3v3
+                  GND   -   GND
+                   G0   -   CLK
+              G36/G25   -   MISO
+                  G26   -   MOSI
+                        -   CS (jumper to SD Card GND Pin)
+      */
+      enum { SPI_SCK = 0, SPI_MISO = 36, SPI_MOSI = 26 };
+      SPIClass SPI_EXT;
+      SPI_EXT.begin(SPI_SCK, SPI_MISO, SPI_MOSI, SD_CS);
+      if (!SD.begin(SD_CS, SPI_EXT)) {
+    #else
+      if (!SD.begin(SD_CS)) {
+    #endif
       Serial.println(F("Failed to mount SD Card"));
       this->supported = false;
       return false;
@@ -274,4 +290,4 @@ void SDInterface::main() {
       this->initSD();
     }
   }
-}
+}